Produced by Don Kretz, Juliet Sutherland, and Distributed Proofreaders

SCIENTIFIC AMERICAN SUPPLEMENT NO. 447

NEW YORK, JULY 26, 1884

Scientific American Supplement. Vol. XVIII, No. 447.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

TABLE OF CONTENTS.

I.    CHEMISTRY.--The Bitter Substance of Hops.--By Dr. H. BUNGENER.
      --What gives hops their bitter taste?--Processes for obtaining
      hop-bitter acid.--Analysis of the same.

II.   ENGINEERING AND MECHANICS.--Improvements in the Harbor
      of Antwerp.--With engraving of caisson for deepening the
      river.

      Progress of Antwerp.--Recent works in the harbor.

      Bicycles and Tricycles.--By C.V. BOYS.---Advantages of the
      different machines.--Manner of finding the steepness of a hill
      and representing same on a map.--Experiments on ball bearings.--
      The Otto bicycle.

      The Canal Iron Works, London.

      Marinoni's Rotary Printing Press.--With 2 engravings.

      Chenot's Economic Filter Press.--With engraving.

      Steel Chains without Welding.--Method and machines for making
      same.--Several figures.

III.  TECHNOLOGY.--Some Economic Processes connected with the
      Cloth Making Industry.--By Dr. WM. RAMSAY.--How to save and
      utilize soap used in wool scouring.--To recover the indigo from
      the refuse.--Extraction of potash from _suint_.--Use of
      bisulphide of carbon.

IV.   PHYSICS. ELECTRICITY, ETC.--Thury's Dynamo Electric Machine.
      --5 figures.

      Breguet's Telephone.

      Munro's Telephonic Experiments.--9 figures.

      Apparatus for Maneuvering Bichromate of Potassa Piles from a
      Distance.--2 figures.

      Magnetic Rotations.--By E.L. VOICE.--1 figure.

      Lighton's Immersion Illuminator.--1 figure.

      Foucault's Pendulum Experiments.--By RICHARD A. PROCTOR.
      --4 figures.

V.    ARCHITECTURE, ART, ETC.--St. Paul's Vicarage, Forest Hill,
      Kent.--2 engravings.

      Designs for Iron Gates.--An engraving.

VI.   ASTRONOMY.--A New Lunarian.--By Prof. C.W. MACCORD.
      --With 3 figures.

VII.  GEOLOGY.--Coal and its Uses.--By JAMES PYKE.--Formation
      of carboniferous rocks and the coal in the same.--Processes of
      nature.--Greatness of this country due to coal.--Manufacture of
      gas.--Products of the same.

VIII. NATURAL HISTORY, BOTANY. ETC.--The Wine Fly.--The
      egg.--Larva.--Pupa and fly.

      The "Potetometer." an Instrument for Measuring the Transpiration
      of Water by Plants.--1 figure.

      Bolivian Cinchona Forests.

      Ferns.--Nephrolepis Davillioides Furcans and Nephrolepis Duffi.
      --2 engravings.

IX.   PHYSIOLOGY, HYGIENE, ETC.--The Upright Attitude of Mankind.
      --Review of a lecture by Dr. S.V. CLEVENGER, in which he
      tries to prove that man must have originated from a four footed
      being.

      Our Enemies, the Microbes.--Affections caused by the same.--
      Experiments of Davaine, Pasteur, and others.--How to prevent
      bacterides from entering the body.--5 figures.

X.    BIOGRAPHY.--Gaston Plante, the Scientist.--With portrait

      Warren Colburn, the American Mathematician.

IMPROVEMENTS IN THE HARBOR OF ANTWERP.

The harbor of Antwerp, which, excepting those of London and Liverpool,
is the largest in Europe, has been improved wonderfully during the last
decade. Before 1870 it was inferior to the harbor at Havre, but now it
far surpasses the same. The river Scheldt, which is about 1,500 ft.
wide, was badgered out up to the vertical walls of the basin, so that
the largest ships can land at the docks. The river was deepened by the
use of caissons, in the lower parts of which the workmen operated in
compressed air. The annexed cut shows that part of one of the caissons
which projects above the surface of the water. The depth of the river at
low tide is about 26 ft., and at high tide about 39 ft. Some of the old
sluices, channels, basins, etc., which were rendered useless by the
improvements made in the river Scheldt have been filled up, and
thereby the city has been enriched by several handsome and elegant
squares.--_Illustrirte Zeitung_.

PROGRESS OF ANTWERP.

Antwerp is now the chief port on the Continent. Since 1873 the progress
has continued, and made very rapid advances. In 1883 the tonnage of the
port reached 3,734,428 registered tons. This marvelous development is
partly due to the position of Antwerp as the embarking point from the
Continent of Europe to America, and partly also to the recent additions
and changes which have been carried out there, and which, now nearly
completed, have made this cosmopolitan port one of the best organized in
the world. This is so well known that vessels bound for Switzerland with
a cargo of corn from Russia pass Marseilles and go two thousand miles
out of their way for the purpose of unloading at Antwerp. No other port,
in fact, offers the same facilities. There is not another place in the
world where fifty vessels of 3,000 tons can come alongside as easily as
the penny boats on the Thames run into the landing.

[Illustration: CAISSONS FOR DEEPENING THE RIVER AT ANTWERP.]

Since the opening of the St. Gothard Tunnel nearly all the alimentary
provisions that Italy sends to the British Isles pass through Antwerp.
In 1882 82,000,000 eggs and 30,000 pounds of fruit were shipped there
for England. The greater part of these came from Italy. Antwerp has
become also an important port for emigrants; 35,125 embarked in 1882,
out of which number 3,055 were bound for New York. The city was always
destined, from its topographical position, to be at the head of a very
considerable traffic; political reasons alone for many years prevented
this being the case. These have happily now disappeared, and, since
1863, when the "Scheldt was liberated," the progress of commerce has
been more rapid than even the most ardent Antwerp patriot dared hope. At
that date the toll of 1s. 11d. on all vessels going up the river, and of
7½d. on vessels going down, was abolished, and reforms were introduced
among the taxes on the general navigation; the tax on tonnage in the
port itself was abolished, and the pilot tax was lowered. The results of
these measures became immediately apparent. Traffic increased with
such rapidity that in 1876 the crowding on the quays was such that the
relation of the tonnage to the length of the quay was about 270 tons per
yard, which is four times as great as at Liverpool.

A few words now, briefly, as to the nature of the important works[1]
completed at Antwerp. They were commenced in 1877, and have opened for
the port an era of prosperity such as was never experienced even during
the sixteenth century, the zenith of her splendor. These works have
cost £4,000,000, and have necessitated the employment of 12,000 tons
of wrought iron, of 490,000 cubic yards of brickwork and concrete, of
32,000 cubic yards of masonry, and of more than 3,300,000 cubic yards
of earthwork in filling and dredging, etc. The quay walls run the whole
length of the town, a distance of rather more than two miles. It rests
on a foundation laid without timber footings, and giving a depth of
twenty-six feet at low water, sufficient drawing for the largest ships
afloat. Beyond this wall are the real quays, which consists of first a
line of rails reserved for hydraulic cranes serving to unload vessels
and deposit their cargo railway trucks; secondly, a second line of rails
parallel with the first, on which these trucks are stationed; thirdly,
sheds extending toward the town for a width of one hundred and fifty
feet, and covered with galvanized iron sheetings. A third line of rails
parallel with the two others runs from end to end of these sheds, and a
number of lines placed transversely with this one connect it by means of
spring bridges with, fourthly, four more lines also parallel with the
quays, whence the goods start for the different stations, and thence to
their destinations. The total width of these immense constructions is
about three hundred and twenty feet. Such is their magnitude that about
six hundred houses had to be pulled down to make place for them. A
railing running along their entire length cuts them off from the town.

[Transcribers note 1: changed from 'words']

During the course of last year 4,379 vessels entered the port of
Antwerp, gauging a total of 3,734,428 tons, which places Antwerp, as I
have already stated, at the head of European ports. In 1882 the tonnage
of Havre was only 2,200,000, that of Genoa 2,250,000, and of Bilboa
315,000, owing to its iron ore exports. Among the English ports a few
only exceed Antwerp. London is still the first port in the world, with
a tonnage of 10,421,000 tons, and Liverpool the second, with 7,351,000
tons; Newcastle follows with 6,000,000 tons, also in excess of Antwerp,
but both Hull and Glasgow are below, with respectively 1,875,000 and
2,110,000 tons.--_Pall Mall Gazette_.

BICYCLES AND TRICYCLES.

[Footnote: A recent lecture before the Society of Arts, London.]

By C.V. BOYS.

The subject of this paper is one of such wide interest, and of such
great importance, that it is quite unnecessary for me to make any
apology for bringing it to your notice. Exactly two months ago, I had
the honor of dealing with the same subject at the Royal Institution. On
that occasion I considered main principles only, and avoided anything in
which none but riders were likely to take an interest, or which was in
any way a matter of dispute. As it may be assumed that the audience here
consists largely of riders, and of those who are following those matters
of detail, the elaboration, simplification, and perfection of which
have brought the art of constructing cycles to its present state of
perfection, I purpose treating the subject from a totally different
point of view. I do not intend, in general, to describe anything,
assuming that the audience is familiar with the construction of the
leading types of machines, but rather to consider the pros and cons
of the various methods by which manufacturers have striven to attain
perfection. As a discussion on the subject of this paper will doubtless
follow--and I hope makers or riders of every class of machine will
freely express their opinion, for by so doing they will lend an interest
which I alone could not hope to awaken--I shall not consider it
necessary to assume an absolutely neutral position, which might be
expected of me if there were no discussion, but shall explain my own
views without reserve.

The great variety of cycles may be grouped under the following heads:

  1. The Bicycle unmodified.
  2. The Safety bicycle, a modification of 1.
  3. The Center-cycle.
  4. The Tricycle, which includes five general types:
  (a.) Rear steerer of any sort.
  (b.) Coventry rotary.
  (c.) Front steerer of any sort (except e).
  (d.) Humber pattern.
  (e.) The Oarsman.
  5. Double machines: sociables and tandems.
  6. The Otto.

It is perfectly obvious that not one machine is superior to all others
in every respect, for if that were the case, the rest would rapidly
become extinct. Not one shows any signs of becoming extinct, and,
therefore, it may be assumed that each one possesses some points in
which it is superior to others, the value of which is considered by
its riders to far outweigh any points in which it may be inferior. The
widely varying conditions under which, and purposes for which, machines
are used and the very different degrees of importance which differently
constituted minds attach to the peculiarities of various machines, will,
probably, prevent any from becoming extinct. Nevertheless, the very
great advantages which some of these possess over others will, no doubt,
in time become evident by the preponderance of the better class of
machines.

The bicycle, which surpasses all other machines in simplicity,
lightness, and speed, will probably, for these reasons, always remain a
favorite with a large class. The fact that it requires only one track
places it at a great advantage with respect to other machines, for it is
common for a road which is unpleasant from mud or stones to have a hard,
smooth edge, a kind of path, where the bicyclist can travel in peace,
but which is of little advantage to other machines. Again, the bicycle
can be wheeled through narrow gates or door ways, and so kept in places
which are inaccessible to tricycles. One peculiarity of the bicycle,
and to a certain extent of the center-cycle, is that the plane of the
machine always lies in the direction of the resultant force, that the
machine leans over to an amount depending on the velocity and the
sharpness of the curve described. For this reason all lateral strain on
the parts is abolished, and if we except the slipping away of the wheel
from under the rider, which can hardly occur on a country road, an upset
from taking a curve too quickly is impossible. This leaning to either
side by the machine and rider gives rise to that delightful gliding
which none but the bicyclist or the skater can experience. In this
respect the bicycle has an enormous advantage over any machine, tricycle
or Otto, which must at all times remain upright, and which must,
therefore, at a high speed, be taken round a curve with discretion.

The perfect and instantaneous steering of the bicycle, combined with
its narrowness, counteract, to a great extent, the advantage which the
tricyclist has of being able to stop so much more quickly, for
the bicyclist can "dodge" past a thing for which the rider of the
three-wheeler must pull up. In one other respect the bicyclist has an
advantage which, though of no real importance, has great weight with
many people. The bicycle well ridden presents a picture of such perfect
elegance that no one on anything else need expect to appear to advantage
in comparison.

The chief disadvantage of the bicycle is the fact that a rider cannot
stop for any purpose, or go back a little, without dismounting. For town
riding, where a stoppage is frequently necessitated by the traffic, this
perpetual mounting and dismounting is not only tiresome, but wearying,
so much so that few bicyclists care to ride daily in town.

The position of the rider on a bicycle, with respect to the treadles,
is by no means good, for if he is placed sufficiently far forward to be
able to employ his weight to advantage without bending himself double,
he will be in so critical a position that a mere touch will send him
over the handles. He has, therefore, to balance stability and safety
against comfort and power; the more forward he is, the more furiously he
can drive his machine, and the less does he suffer from friction and the
shaking of the little wheel; the more backward he is, the less is he
likely to come to grief riding down hill, or over unseen stones. The
bicyclist is no better off than the rider of any other machine with a
little wheel, the vibration from which may weary him nearly as much as
the work he does. The little wheel as a mud-throwing machine engine is
still more effective on the bicycle than it is on any tricycle, for in
general it is run at a higher speed.

I now come to the usual complaint about the bicycle. There is a fashion
just now to call it dangerous and the tricycle safe. But the difference
in safety has been much exaggerated. The bicyclist is more likely to
suffer from striking a stone than his friend on three wheels, but then
he should not strike one where the tricyclist would strike a dozen.
Properly ridden, neither class of machine can be considered dangerous;
an accident should never happen except it be due to the action of
others. People, carts, cattle, and dogs on the road are liable to such
unexpected movements, that the real danger of the cyclist comes from the
outside; to danger from absolute collapse, due to a hidden flaw in
the materials employed, every one is liable, but, the bicyclist more
remotely than the tricyclist, owing to the greater simplicity of his
machine. The bicyclist, though he has further to fall in case of an
accident from any of these causes, is in a better position than the
tricyclist, for he is outside instead of inside his machine; he can in
an instant get clear.

It would appear that many tricyclists consider accidents of the kind
next to impossible, for in several machines the rider is so involved
that an instantaneous dismount without a moment's notice, at any speed,
is absolutely impossible. There remains one objection, which, however,
should be of next to no importance--the difficulty of learning the
bicycle prevents many from taking to the light and fast machine, because
they are afraid of a little preliminary trouble.

The chief objections to the bicycle, then, are the liability of the
rider to go over the handles, the impossibility of stopping very
quickly, and the inability to remain at rest or go backward, and the
difficulty of learning.

The first two of these are, to a large extent, overcome in the safety
bicycles, but not without the introduction of what is in comparison a
certain degree of complication, or without the loss of the whole of the
grace or elegance of the bicycle. On almost all of these safety bicycles
the rider is better placed than on the unmodified bicycle, but though
safer, I do not think bicyclists find them complete in speed, though, no
doubt, they are superior in that respect to the tricycle. Though they do
not allow the rider to stop without dismounting, the fatigue resulting
from this cause is less than it is with a bicycle, owing to the fact
that with the small machines the rider has so small a distance to climb.
Of these machines, the Extraordinary leaves the rider high up in the air
on a full-sized wheel, but places him further back and more over the
pedals. The motion of these is peculiar, being not circular, but oval, a
form which has certain advantages.

In the Sun and Planet and Kangaroo bicycles a small wheel is "geared
up," that is, is made to turn faster than the pedals, so as to avoid the
very rapid pedaling which is necessary to obtain an ordinary amount
of speed out of a small wheel. In each of these the pedals move in a
circular path, and their appearance is in consequence less peculiar than
that of the Facile, which, in this respect, does not compare favorably
with any good machine. The pedal motion on the Facile is merely
reciprocating. Riders of machines where circular motion is employed,
among them myself, do not believe that this reciprocating motion can
be so good as circular, but I understand that this view is not held by
those who are used to it. Of course, the harmonic motion of the Facile
pedal is superior to the equable reciprocating motion employed in some
machines where speed is an object, especially with small wheels.

If I have overlooked anything typical in the modified bicycle class,
I hope some one will afterward supply the omission, and point out any
peculiarities or advantages.

That very peculiar machine, the center-cycle, seems to combine many of
the advantages of the bicycle and tricycle. On it the rider can remain
at rest, or can move backward; he can travel at any speed round curves
without an upset being possible; he can ride over brickbats, or
obstructions, not only without being upset, but, if going slowly,
without even touching them. As this machine is very little known, a few
words of explanation may be interesting.

In the first place, the rider is placed over the main wheel, as in the
bicycle, but much further forward. There are around him, on or near the
ground, four little wheels, two before and two behind, supported in a
manner the ingenuity of which calls for the utmost admiration. Turning
the steering handle not only causes the front and rear pairs to turn
opposite ways, but owing to their swiveling about an inward pointing
axis, the machine is compelled to lean over toward the inside of the
curve; not only is this the case, but each pair rises and falls with
every inequality of the road, if the rider chooses that they run on the
ground; but he can, if he pleases, arrange that in general they ride in
the air, any one touching at such times as are necessary to keep him on
the top of the one wheel, on which alone he is practically riding. He
can, if he likes, at any time lift the main wheel off the ground and run
along on the others only. The very few machines of the kind which I have
seen have been provided with foot straps, to enable the rider to pull as
well as push, which is a great advantage when climbing a hill, but this
is on every machine except the Otto, of which I shall speak later,
considered a dangerous practice.

Some of the objections to the bicycle to which I have referred were
sufficient to prevent many, especially elderly men, from dreaming of
becoming cyclists. So long as the tricycle was a crude and clumsy
machine, there was no chance of cycling becoming a part, as it almost is
and certainly soon will be, of our national life. The tricycle has been
brought to such a state of perfection that it is difficult to imagine
where further progress can be made.

Perhaps it will be well to mention what is necessary in order that a
three-wheeled machine may be made to roll freely in a straight line, and
also round curves. At all times each wheel must be able to travel in
its own plane in spite of the united action of the other two. To run
straight, the axes of all the wheels must obviously be parallel. To run
round a curve, the axis of each must, if continued, pass through the
center of curvature of the curve. If two wheels have a common axis, the
intersection of the two lines forming the axes can only meet in one
point. To steer such a combination, therefore, the plane of the third
wheel only need be turned. If the axis of no two are common, then the
planes of two of the wheels must be turned in order that the three axes
may meet in a point.

Not only does free rolling depend on the suitable direction of the
planes of the wheels, each wheel must be able to run at a speed
proportional to its distance from the point of intersection of the three
axes, i.e., from the ever-shifting center of curvature.

The most obvious way, then, of contriving a three wheeler is to drive
one wheel, steer with another, and leave the third, which must be
opposite the driver, idle. The next in simplicity is to drive with one
wheel, and steer with the other two, having one in front and the other
behind. So far then, the single driving rear-steerer and the Coventry
rotary pattern are easily understood. The evils of single driving,
minimized, it is true, to a large extent, in the Coventry rotary, have
led to the contrivance of means by which a wheel on each side may be
driven without interfering with their differential motion in turning a
corner.

Three methods are commonly used, but as only two are employed on
tricycles, I shall leave the third till I come to the special machine
for which it is necessary. The most easy to understand is the clutch,
a model of which I have on the table. If each main wheel is driven by
means of one of these, though compelled to go forward by the crankshaft,
it is yet free to go faster without restraint. By this means "double
driving" is effected in several forms of tricycle.

Differential gear, which is well understood, and of which there are
several mechanically equivalent forms, divides the applied driving
power, whether forward or backward, between the main wheels, equally if
the gear is perfect, unequally if imperfect. To understand the effect
of the two systems of driving, and of single driving, let us place on
grooves a block which offers resistance to a moving force. If we wish
to move it, and apply our force at the end of one side, it will tend to
turn round as well as move forward, and much friction will be spent on
the guides by their keeping it straight.

This is the single driver. If, instead of applying force at one side, we
push the block bodily forward by a beam moving parallel to itself, then
so long as the guides are straight no strain will be put upon them,
even though one side of the block is resisted more than the other; if,
however, the guides compelled the block to travel round a curve, then
the power, instead of being divided between the two sides in such
proportion as is necessary to relieve the guides of all strain, is
suddenly applied only to the inside, and the effect is that of a single
driver only. This is the clutch. Lastly, if the last-mentioned beam,
instead of being pushed along parallel to itself, were pivoted in the
middle, and that pivot only pushed, the same power would be applied to
each side of the block, and no strain would be thrown on the guides,
whether straight or curved, so long as the resistance opposed to the
block on the two sides were equal; if, however, one side met with more
resistance than the other, then the guides would have to keep the block
straight. This is the differential gear.

I have assumed that in the last case the force was applied to the middle
of the beam; this corresponds to every evenly-balanced gear. In the gear
employed by Singer, which is not evenly balanced, but which derives its
good qualities from its simplicity, the same effect is produced as
if the beam were pivoted on one side of the center instead of on the
center. Thus, though both sides are driven, one is driven more than the
other. On the whole, there is no doubt that the balanced gear gives a
superior action to the clutch, for except when the two sides of the
machine meet with very different resistance, and then only when running
straight, the clutch will not compare with the other. The clutch also
gives rise to what is considered by most riders a grave defect, the
inability to back treadle, while the free pedal, which is an immediate
consequence, is considered by others a luxury.

On the other hand, this same free pedal can be obtained on
differentially driven machines to which speed and power gear have been
applied.

Of the relative merits of different forms of differential gear there is
little to be said. Perhaps it will not be thought I am unduly thrusting
myself forward, if I refer to a scheme of my own, in which no toothed
wheels are employed, but in which two conical surfaces are driven by a
series of balls lying in the groove between them, and jambed against
them by a recessed ring.

I have here a large wooden diagrammatic model, and a small working
model in steel, which shows that the new principle employed is correct,
namely, that a ball while jambed is free to turn, or if turning is able
to jamb. All Humbers, and most front steerers, employ differential
gearing; in some front steerers the clutch of necessity is used.

Neglecting for the present the different modes of transmitting power
from the pedals to the main wheels, it is possible now to consider the
four typical builds of tricycle. The only advantage that a rider can
find in a rear-steerer is the open front, so that in case of accident
he can more easily clear himself of his machine; as I have already
remarked, this power of instantly escaping seems to be considered by
many as of no importance.

In a rear-steerer which has not an open front, whether driven by a
clutch or by differential gear, I fail to discover any good quality.
The steering of a rear-steerer is so very uncertain, that such machines
cannot safely be driven at anything like a high speed, because any wheel
meeting with an obstruction will, by checking the machine, diminish the
weight on the steering wheel just at the time when a greater weight than
usual should be applied. It is for the corresponding reason that the
steering of a front-steerer is so excellent; the more the machine is
checked by obstruction, by back treading, or by the brake, the greater
is the weight on the front wheel.

For shooting hills, or for pulling up suddenly, no machine of any kind
will compare with a good front-steerer. In all respects it is superior
to the rear-steerer if we except the open front, but against this may
be set the fact that on many the rider can mount from behind, or can
dismount in the same manner while the machine is in motion. Experience
shows that the front-steerer is for general excellence, safety, easy
management, and light-running, the best all-round tricycle that is to be
had.

The Humber build, which departs less from the ordinary bicycle than any
othar, is far superior to all others for speed; it is, however, somewhat
difficult to manage, for the steering is not only delicate, but
critical, requiring constant care lest a stone or other obstruction
should take the rider unawares, and steer the machine for him.

The control which a skillful rider of the Humber has over his machine is
wonderful; the elegance of the machine among tricycles is unequaled.
So great a favorite is this form, especially among the better class of
riders, that almost every firm have brought out their own Humber, each
with a distinguishing name.

The only improvement or change, whichever it may be, that has been made
by others with which I am acquainted, is the triple steering, in which
the hind wheel moves the opposite way to the others. The corresponding
change in the bicycle was soon discarded; I do not know what advantage
can result from the increased delicacy of steering here. I should have
thought it delicate enough already.

One noticeable change in the front-steering tricycle, which has been
largely made, lately, is the substitution of central for side gearing,
in consequence of which bicycle cranks can be employed, instead of
the cranked axle, with its fixed throw. This gives an appearance of
lightness which the older types of machine do not possess.

I now come to that very difficult and all-important subject, the method
of transmitting power from the body of the rider to the main axle. Next
to the structural arrangement, this is most important in distinguishing
one type of machine from another.

The first to which I shall refer is the direct action employed on the
National and the Monarch tricycles. It is obvious that by having no
separate crank shaft, much greater simplicity and cheapness and less
friction are attained than can be possible when the extra bearings and
gear generally used are employed. In this respect the direct action
machines undoubtedly have an advantage, but an advantage of any kind may
be too dearly bought, as it certainly is here.

In the first place, the direct action can only be applied to a
rear-steering, clutch-driven machine, or single driver, for if the
wheels were not free to run ahead, it would be impossible to go round a
curve. In the second place, the rider must be placed at such a height
for his feet to work on the axle that the machine, of necessity, is very
unstable, and is likely to upset if ridden without great caution round
a curve. Thirdly, to diminish as far as possible this last objection,
miserable little wheels must be employed, which cannot be geared up,
that is, made to travel faster than the treadles, and so be equivalent
to larger wheels. Therefore, though it is likely that at such low speeds
only as it is safe to run such a machine it may move more easily than a
machine of a recognized type, and though direct action would undoubtedly
be advantageous if it did not entail defects of a most serious order of
magnitude, we may dismiss this at once from our consideration. It is
true that in the Monarch a few inches of height are gained by the
hanging pedals, but I question very much whether one machine is much
better than the other.

The chain which is used on almost every make of machine cannot be
considered perfect; it is, on the whole, a dirty and noisy contrivance,
giving rise to friction where the links take and leave the teeth of
the pulleys; stretching, or rather lengthening, by wear, and, finally,
allowing back lash, which is most unpleasant. In spite of all this, it
affords a convenient and reliable means of transmitting power, which is
applicable to every type of tricycle, except one.

Instead of a chain, an intermediate or idle wheel has been tried, but
this has not been found advantageous. The intermediate wheel has been
removed, and the crank and wheel pulley allowed to gear directly
together, making reverse motion of the feet necessary, and possibly
reducing friction.

The crank and connecting rod are employed in some machines. If there are
two only, they must not be placed in opposite positions, but be fixed at
an angle, so that there are times when each rod is under compression,
a strain which delicate rods cannot stand. In the three-throw crank,
employed in the Matchless tricycle, this objection is obviated, for one,
at least, is at all times in such a position as to be in tension. The
objection to the crank is the fact that it weakens the shaft, and that
it can only be used with a clutch, not with a differential gear.

The most silent, neatest, and cleanest driver, the one of which the
working friction is least, is the endless steel band, so well known in
connection with the Otto bicycle. This is not, as far as I am aware,
employed on any tricycle, makers probably fearing lest it should slip.
The Otto shows that it can safely be employed.

I have devised a scheme, of which I now show a model, which seems to me
to be free from the objections which may be urged against other methods;
but I, of course, cannot be considered in this respect a judge.
Eccentrics are well known as equivalent to cranks, but if used in the
same way, with a connecting rod, either fatal friction or enormous
ball-bearings would be necessary. Instead of these, I connect two pair
of equal eccentrics by an endless band embracing each, so that the band
acts like a connecting rod without friction, and, at the same time,
acts by its turning power as on the Otto, thus making two eccentrics
sufficient instead of three, and carrying them over the dead points.

There is one more system of transmitting power employed on a few
machines. In these, a band or line passes over the circumference of a
sector or wheel, and the power is directly applied to it. The motion of
the feet in the omnicycle, and of the hands and body in the Oarsman, is
therefore uniform. There would be no harm in this if it were not for the
starting and the stopping, which cannot be gradual and at the same time
effective in machines of this type. For this reason, a high speed cannot
be obtained; nevertheless, these machines are better able to climb hills
than are tricycles with the usual rotary motion, for, at all parts of
the stroke--which may be of any length that the rider chooses--his
driving power on the wheels is equal. The ingenious expanding drums on
the omnicycle make this machine exceptionally good in this respect, for
increased leverage is effected without increased friction, which is the
result of "putting on the power" in some of the two-speed contrivances.

Having spoken of the Oarsman tricycle, I must express regret that I have
not been able to find an opportunity to ride on or with the machine, so
that I cannot from observation form an opinion of its going qualities.
There can be no doubt that the enormous amount of work that can be got
from the body in each stroke on a sliding seat in a boat must, applied
in the same manner on the Oarsman tricycle, make it shoot away in a
surprising manner; whether such motion, when continued for hours, is
more tiring than the ordinary leg motion only, I cannot say for certain,
but I should imagine that it would be. The method by which the steering
is effected by the feet, and can with one foot be locked to a rigidly
straight course, is especially to be admired.

There is much difference of opinion with respect to the most suitable
size for the wheels of machines. Except with certain machines, this has
nothing to do with the speed at which the machine will travel at a given
rate of pedaling, for the wheels may be geared up or down to any extent,
that is made to turn more quickly or slowly than the cranks. Thus the
most suitable speeding is a separate question, and must be treated by
itself.

Large wheels are far superior to small wheels in allowing comfortable,
easy motion, a matter of considerable importance in a long journey. They
are also far better than small for running over loose or muddy ground,
for with a given weight upon them they sink in less, from the longer
bearing they present, and this, combined with their less curvature,
makes the everlasting ascent which the mud presents to them far less
than with a smaller wheel. On the other hand, the large wheel is
heavier, and suffers more from air resistance than the small wheel. For
racing purposes a little wheel, geared up of course, is certainly better
than a high wheel; for comfortable traveling, and in general, the high
wheel is preferable. Though this is certainly the case, it does not
follow that large wheels are worth having on a machine when there is
already one little wheel. If the rider is to be worried with the evils
of a little wheel at all, it is possible that any advantage which large
wheels would give him would be swamped by the vibration and mud-sticking
properties of the small steering wheel. One firm, in their endeavors
to minimize these evils, have designed machines without any very small
wheels; all three wheels are large, and a steadier and more comfortable
motion no doubt results.

High and low gearing are the natural sequel to high and low wheels. Of
course the lower the gearing the greater is the mechanical advantage in
favor of the rider when meeting with much resistance, whether from wind,
mud, or steepness of slope. In spite of this, for some reason which I
cannot divine, the machines with excessively low gear do not seem to
obtain so great an advantage in climbing hills as might be expected. To
make such a machine travel at a moderate speed only, excessively rapid
pedaling is necessary, and the rider is made tired more by the motion of
his legs than by any work he is doing. The slow, steady stroke by which
a rider propels a high-geared machine is far more graceful and less
wearying than the furious motion which is necessary on a low-geared
machine. The height up to which the driving-wheels are usually geared
may be taken as an indication of the ease with which any class of
machines runs. A rider on a low-geared machine can start his machine
much more quickly than an equal man on one that has high gearing, and
therefore in a race he has an advantage at first, which he speedily
loses as his rapid pedaling begins to tell. For ordinary riding the
slight loss of time at starting is a matter of no importance whatever.

There are several devices which enable us to obtain the advantages of
high and low gearing on the same machine, which at the same time give
the rider the benefit of a free pedal whenever he wishes. On some single
driving rear-steering tricycles the connection on one side is for speed,
and that on the other for power, either being in action at the wish of
the rider, or both speed and power combinations are applied on the same
side. To drive with a power gear a single wheel only seems to me to be
the height of folly; in my opinion no arrangement of this type is worthy
of serious attention. Among the better class of machines there are three
methods by which this change is effected--first, that employed on the
omnicycle, to which I have already referred; secondly, an epicyclic
combination of wheelwork which moves as one piece when set for speed,
thus adding nothing to the working friction except by its weight, but
which works internally when set for power, thus reducing to a small
extent, by the additional friction, the gain of power which the rider
desires; thirdly, a double set of chains and pulleys, each set always in
movement, so that, whether set for speed or power, there is rather more
friction than there would be if there were no additional chains, but
these are free from that increased friction due to toothed wheel
gearing, from which the epicyclic contrivances suffer only when set
for power. There is much difference of opinion whether any of these
arrangements are worth carrying, for perhaps nine miles, for the sake of
any advantage that may be obtained in the tenth. It is on this account
that the drums on the omnicycle are so excellent; whether expanded or
not, there is, on their account, no loss of work whatever, for there is
no additional friction. The subject of these two speed gears will, I
hope, be discussed; it is one which, though not new, is coming more to
the front, and about which much may be said.

Having now dealt with the means by which tricycles are made to climb
hills more easily, I wish to leave the subject of bicycles and tricycles
altogether for a few minutes, to say a few words which may specially
interest those who are fond of trying their power in riding up our best
known hills. The difficulty of getting up depends to a large extent on
the surface and on the wind, but chiefly on the steepness. The vague
manner in which one hill is compared with another, and the wild ideas
that many hold who have not made any measurements, induces me to
describe a method which I have found specially applicable for the
measurement of steepness of any hill on which a cyclist may find
himself, and also a scheme for the complete representation of the
steepness and elevation of every part of a hill on a map so as to be
taken in at a glance. The force required to move the thing up a slope is
directly proportional not to the angle, but to the trigonometrical sine
of that angle. To measure this, place the tricycle, or Otto--a
bicycle will not stand square to the road, and therefore cannot be
used--pointing in direction at right angles to the slope of the hill, so
that it will not tend to move. Clip on the top of the wheel a level, and
mark that part of the road which is in the line of sight. Take a string
made up of pieces alternately black and white, each exactly as long as
the wheel is high, and stretch it between the mark and the top of the
wheel. If there are n pieces of string included, the slope is 1 in n,
for by similar triangles the diameter of the wheel is to the length of
the string as the vertical rise is to the distance on the road. This
gives the average steepness of a piece sufficiently long to be worth
testing, because an incline only a few feet in length, of almost any
steepness, can be mounted by the aid of momentum.

There is only one process, with which I am acquainted, which supplies a
method of representing on a map the steepness of a road at every part.
Contours, of course, show how far one has to go to rise 50 or 100 feet,
but as to whether the ascent is made uniformly or in an irregular
manner, with steep and level places, they tell us nothing. Let the
course of a road be indicated by a single line where it is level, and by
a pair of lines where inclined. Let the distance between the lines be
everywhere proportional to the steepness, then the greatest width will
show the steepest part, and an intermediate width will show places
of intermediate steepness; the crossing of the lines, which must be
distinguishable from one another, will show where the direction of the
slope changes. Further, the size of the figure bounded by the two lines
will show the total rise; a great height being reached only by great
steepness or by great length, a large figure being formed only by great
width or by great length. Those who are mathematically inclined will
recognize here that I have differentiated the curve representing the
slope of the bill, and laid the differential curve down in plan.

Having wandered off my subject, I must return to more mechanical things,
and give the results of some experiments which I have made on the balls
of ball bearings. There is no necessity to argue the case of ball vs.
plain bearings, the balls have so clearly won their case, that it would
be waste of time to show why. Of the wear of the twelve balls forming
one set belonging to the bearings of the wheels of my Otto, I have on a
previous occasion spoken; I may, however, repeat that in running 1,000
miles, the twelve balls lost in weight only 1/20.8 grain, or each ball
lost only 1/250 grain. The wear of the surface amounted to only 1/158000
inch; at the same rate of wear, the loss in traveling from here to the
moon would amount to only 1/34.3 of their weight. I examined each ball
every 200 miles, and was surprised to find that on the whole the wear of
each, during each journey, varied very little. The balls experimented on
were a new set obtained from Mr. Bown. I also had from him one ball of
each of each of the following sizes 3, 4, 5, 6, and 7 16ths of an inch
in diameter, as I was curious to know what weight they would suppport
without crushing. As as preliminary experiment, I placed a spare 5/16
ball between the crushing faces of the new testing machine at South
Kensington, and applied a gradually increasing force up to 7 tons 9½
cwt., at which it showed no signs of distress. On removing it I found
that it had buried itself over an angle of about 60° in the hard steel
faces, faces so hard that a file would not touch them. Those marks will
be a permanent record of the stuff of which the ball was made. The ball
itself is sealed in a tube, so that any one who is curious to see it can
do so. Finding that the crushing faces were not sufficiently hard, I
made two anvils of the best tool steel, and very carefully hardened
them. These, though they were impressed slightly, were sufficiently good
for the purpose. In the following table are the results of the crushing
experiments:

3/16 ball at 2 tons 13 cwt. did not break, but crushed on removing part
of the weight.

¼ ball at 3 tons 15 cwt. did not break, but crushed on removing part of
the weight.

5/16 ball at 4 tons 9 cwt. broke.

3/8 ball at 8 tons 6 cwt. did not break, crushed under another 120 lb.

7/16 ball crushed before 3 tons, with which I was starting, had been
applied. Examination showed that the steel bar of which it was made had
been laminated.

These experiments do not tell much of importance; they are curious,
and perhaps of sufficient interest to bring before your notice. The
fragments are all preserved in tubes, and labeled, so that any one who
likes to see them can do so.

Of the advantage which a machine which will collapse or fold up when
desired, but retain its form on the road, offers in convenience, it is
unnecessary for me to speak.

Of double machines, the Rucker tandem bicycle seems to me to be in every
respect the best, but I should add that I speak only from imagination
and not from experience. The independent steering, the impossibility of
capsizing forward or sideways, the position of the rider over his work,
the absence of any little wheel with its mud throwing and vibrating
tendencies, combine to make a machine which ought to be superior in
almost every desirable quality to any other; what it may be in practice
I hope to hear in the discussion.

Of double tricycles, the Sociable has been tried by many, and is
practically a failure in so far as traveling quickly and easily
is concerned. The Tandem, though it presents so objectionable an
appearance, seems likely to become a favorite, for it surpasses any
single tricycle, and rivals the bicycle in speed. How it may compare in
comfort or in safety with the single machine, perhaps those few who are
well acquainted with them will say; at any rate, in the case of the
Humber, greater stability is given to the steering, owing to the weight
of the front rider.

Time will not allow me to say more of these machines, or to attack the
subject of steam, electric, or magic tricycles, which I had hoped to do.
With steam and electricity we are well acquainted; by magic tricycles, I
mean those driven by a motor which, without any expense, will drive one
twenty miles an hour, up or down hill, with perfect safety. Highway
regulations, and certain reasons not well understood, have at present
prevented these contrivances from making a revolution.

There remains one machine which must be considered separately, for it
cannot be classed with any other. This is the Otto bicycle. My opinion
of this machine is so pronounced that I do not care to state it fully. I
shall merely give the reasons why I prefer it to anything else, and in
so doing I shall be taking the first step in the discussion, in which it
will be interesting to hear from riders of other machines the reasons
for their preference.

In the first place, the evils of a third or little wheel, the cause of
trouble in all tricycles, are avoided. There is none of the vibration
which makes all other machines almost unbearable to Ottoists, vibration
which tricyclists have learnt to consider a necessary accompaniment of
cycling, but which has, no doubt, been diminished by the use of the
spring support of the front steering Humber. It would be presumptuous
in me to make any remarks on the effect of this vibration on the human
system; we shall all be anxious to hear what our Chairman has to say on
this point. By having only two wheels, we have only two tracks, so that
we can travel at a fair speed along those places in the country called
roads, which consist of alternate lines of ruts and stones, where a
three-track machine could not be driven, and where, from the quantity
of loose limestone in the ruts, a little wheel of a two-track tricycle
would be likely to suffer. By having no little wheel, we can ride in
dirty weather without having the rest of our machine pelted with mud, so
that cleaning takes less time than it does with anything else. As I have
already remarked, the small wheel is the culprit which makes the bicycle
and tricycle drive so heavily on a soft road. The ease with which the
Otto can therefore be run through the mud astonishes every one. Having
no little wheel, we can obtain the full advantage of the high 56
inch wheel, which almost every one prefers. As I have ridden all
combinations, from a 50 inch geared up to 60 inch, to a 60 inch geared
level, I can speak from experience of the increased comfort to be
derived from these large wheels, though for speed only they do not
compare with the smaller and lighter wheels geared up. A further point
gained by the use of two wheels only is the fact that the whole weight
of machine and rider is on the driving-wheel, as it is also on the
steering-wheel, so that by no possibility can the wheels be made to slip
in the driving, or to fail in steering from want of pressure upon them.

The most important consequence, however, is the absence of any fixed
frame. In all machines, bicycles and tricycles, with the usual fixed
frame, a position is found for the saddle which is, on the whole, most
suitable. For some particular gradient it will be perfect; on a steeper
gradient the treadles will be further in advance, but with a steeper
gradient the rider should be more over the front of the treadles. To get
his weight further to the front, he has to double up in the middle, and
assume a position in which he cannot possibly work to advantage. The
swinging frame of the Otto carries the treadles, of necessity, further
back, so that the Ottoist, when working at his hardest, is still
upright, with his hands in the line between his shoulders, and his feet
and his arms straight, so that he can hold himself down, and employ his
strength in a perfectly natural position. On going down a slope, the
fixed frame of a bicycle or tricycle leans forward, and places the rider
in such a position that extra weight is thrown on his arms and his
shoulders, whereas the swing frame of the Otto goes back, and the rider
of necessity assumes that position in which his arms are relieved of all
strain. In so far as the general position taken by the automatic Otto
frame is concerned, nearly the same effect can be obtained by using the
swing frame of the Devon tricycle, which can be shifted and locked in
any position which the rider wishes, or by the sliding saddle, which can
be slid backward or forward and locked so as to place the rider in one
of three positions. Though the rider can by these devices assume nearly
that position with respect to the treadles which is most advantageous,
he cannot obtain that curious fore and aft oscillation made use of by
the Ottoist in climbing hills, which, as the model on the table shows,
enables him to get past the dead points without even moving, and which,
therefore, makes the Otto by far the best hill-climbing machine there
is, if account is taken of the high speeding with which all Ottoists
ride. This is a proposition which none who knows the machine will
question for one moment.

The freedom of motion resulting from the swing of the frame of the Otto
gives a pleasurable sensation, which those who have only experienced the
constrained motion of a three-wheeler cannot even understand.

The very peculiar method of driving and steering, which seems so
puzzling to the novice, especially if he is a good rider of other
machines--for in that case he is far worse off than one who has never
ridden anything--give the rider, when he is familiar with them, a
control over the machine which is still surprising to me. In the first
place, the machine will run along straight, backward or forward, so
long as the handles are let alone. This automatic straight running is a
luxury, for until a deviation has to be made, the steering handles need
not be touched, and the rider may, if sufficiently confident, travel
with his arms folded or his hands in his pockets. The rigid connection
between the cranks and the wheels does away with all the backlash,
which is so unpleasant with chain or toothed wheel gearing. There is no
differential gear or clutch, but the machine possesses the advantage
of the clutch over the differential gear when meeting with unequal
resistance on a straight course, for each wheel must travel at the same
speed; but, in turning a corner, instead of driving the inner wheel
only, which is done by the clutch or both wheels equally, which is the
case with differential gear, each wheel is driven, but the outer one
more than the inner. At high speeds, the steering of the Otto has this
advantage, that whereas, with a given action on a tricyle, the same
deviation will be effected in the same _space_ at high as at low speeds,
the same action on the Otto will, at high speeds, produce the same
deviation in the same _time_ as it does at low speeds; and so instead of
becoming more sensitive at high speeds, as is the case with the tricyle,
the steering of the Otto remains the same. This is because the steering
of the tricycle depends on a kinematical, that of the Otto on a
dynamical principle.

In another respect, no machine can approach the Otto; at almost any
speed the rider can, if there is reason, instantly dismount, by which
action he puts on the brakes, and the machine will save him from
falling, stopping with him almost instantly. As is well known, we can
move backward and forward, we can twist around and around in our own
width, or can ride over bricks with impunity.

One objection to the machine is the difficulty of learning, which is
considerable, but which presents no danger. This difficulty has been
much exaggerated, for before the present powerful brake was applied it
did require considerable skill to ride it down a steep hill. The way
to do this must still be learnt, but it is now comparatively easy. For
going down steep hills, the front steering tricycle is without a rival;
I do not know what other machine will do this better than the Otto.
Lastly, the foot straps, which would be a great advantage on any
machine, if only they were safe, are not--though none but riders will
believe it--in any way a source of danger on the Otto. Having ridden
this machine for close upon 10,000 miles, I can speak with more
authority on this point than can those who are not able to sit upon it
for a moment.

The only disadvantage which the machine presents is the fact that it is
impossible to remove the feet from the pedals while running, without
dismounting; but though they must at all times follow the pedals, the
Ottoist is not, as is generally thought, working when descending a hill.

The enthusiastic terms in which every one who has mastered the
peculiarities of the Otto speaks of it would be considered as evidence
in its favor, if we were not all considered by other cyclists to be in
various stages of lunacy.

THE CANAL IRON WORKS, LONDON.

Some interest is awakened in engineering circles in London, just now, by
the approaching close of the old engineering works so well known as the
"Canal Ironworks," at the entrance to the Isle of Dogs, London, E. This
notable establishment stands second in priority in London--that of
Messrs. Maudslay, Sons & Field being the oldest--for the manufacture of
marine engines. It was founded by the late Messrs. Seawards, above sixty
years ago. Here was originated Seaward's hoisting "sheers" with the
traveling back leg, a modern example of which, 100 feet high, in iron,
stands on the wharf. An interesting tool, also, is the large vertical
boring machine for largest size cylinders; Seaward spent £5,000 upon
this, and it is certainly an admirable tool. There is also the large
vertical slotting machine, with a stroke up to 5 feet 2 inches, a
wonderfully powerful and compact machine. The extensive collection of
screwing tackle is, perhaps, unsurpassed, and extends up to 8 inches
diameter. There is a peculiar erecting shop roof, which will still repay
examination.

MARINONI'S ROTARY PRINTING PRESS.

The greatest progress that has been made in recent years in the art
of printing is in the invention of the high speed press provided with
continuous paper.

Three French constructors, Messrs. Marinoni, Alauzet, and Derriey, have
brought this kind of apparatus to such a degree of perfection that
the majority of foreign journals having a large circulation buy their
presses in France. We reproduce in Fig. 1 a perspective view of the
Marinoni press, and in Fig. 2 a diagram showing the parts of the same.
In order to give a complete description of it, we cannot do better than
to reproduce the very interesting study that has been made of it by Mr.
Monet, a civil engineer.

[Illustration: FIG. 1.--MARINONI'S ROTARY PRINTING PRESS.]

The roller, J (Fig. 2), is placed in the machine in the state in which
it is received from the paper manufactory. The paper unwinds, runs over
the rollers, e and e', which serve only for tautening it, and then
passes between the two cylinders, A and B. The cylinder, A, carries the
form, and B carries the blanket, and the paper thus receives its first
impression. It afterward passes between the cylinders, A' and B', and
receives an impression on the other side, the cylinder, A', carrying the
form, and B' the blanket. Being now printed on both sides, it passes
between the cylinders, KK', which cut it off and allow the sheet to
slide between the cords of the rollers. These latter lead the sheets
over the rollers, g h, on which they wind, one over the other, when the
rollers, a a', are in the position shown by unbroken lines in the cut.

The part of the machine that holds the rollers, g h, and the different
cords that wind over them, is the _accumulator_, and it is in this part
of the press that the sheets accumulate, one over the other, to any
number desired.

The size of the rollers, g h, and their distance apart are so regulated
that when the sheet reaches the accumulator, it falls exactly on those
that have preceded it. When the proper number of sheets is in the
accumulator (4 or 5 being the number most employed for afterward
facilitating the separation into packets on the receiving table), the
two small rollers, a a', advance over the rack, N, and the sheets,
instead of continuing to roll over into the accumulator, fall on the
rack and are deposited by it upon the receiving table, O.

[Illustration: FIG. 2.--MARINONI'S PRESS.]

The rack having fallen twenty times, and deposited five sheets each
time, or one hundred in all, the table moves in such a way as to prevent
the sheets subsequently deposited from getting mixed with them. When the
rack has fallen twenty times, the table returns to its initial position.

The distributing rollers, D, come in contact with the inking rollers, I,
once during each revolution of the printing cylinders, and are mounted
on racking levers provided with regulating screws that permit of easily
regulating the amount of ink taken up. The supports of the inking
rollers are movable and can be made to approach or recede from the
distributing rollers, so as to still further vary the amount of ink
taken up by them.

The distributing rollers supply the ink to a roller, E, of large
diameter, which, having a backward and forward motion, begins to
distribute the ink and to transmit it to a second roller, F, of the same
diameter. This latter then spreads it over a metallic cylinder, G, which
is of the same diameter as the printing cylinders, and against which
revolve three distributing rollers, H, that have a backward and forward
motion.

Between the cylindrical inking table, G, and the type cylinder, there
are situated inking cylinders, T, of large diameter, that constantly
take up ink from the inking table and distribute it over the types.

The machine here described, when designed for printing large sized
journals, has cylinders whose circumference corresponds to the size of
paper for two widths of pages, and whose length is sufficient to allow
it to receive two forms. Each cylinder, then, carries four forms, or
eight in all, and prints two complete copies at each revolution.

The large sheet cut off by the cylinders, K K', contains, then, two
copies; and this sheet, on passing under the roller, f is again cut in
two by a disk which separates it in a direction perpendicular to the
cylinders.

To this press there may be added a mechanical folder of Mr. Marinoni's
invention, capable of folding a journal five times.--_Annales
Industrielles_.

CHENOT'S ECONOMIC FILTER PRESS.

Mr. E. Chenot, who is occupied in the manufacture of wine from dry
grapes, has been led to devise a new style of filter, which by reason of
its mode of action and its construction, he calls the "Economic Filter
Press."

The apparatus, which is shown in the accompanying cut, consists of flat
bags whose mouth may be at the top, as usual, or at the side. Through
this orifice there is introduced a flat piece of wood or metal, which,
like the bag, has an aperture through the center. The whole is suspended
from a distributing pipe that is fixed at one end to the frame and is
free at the other. This pipe is slotted beneath, and the pieces of wood
or metal contain, opposite the slot, a number of small apertures that
put the distributer in communication with the interior of the bags.
Between these latter there are placed wire cloth frames which hold them
in position and facilitate the flow of the filtered liquid. The cut
shows the filter provided with a portion of its bags and frames. When
all the frames are in place they are locked by causing the movable plate
to move forward by means of two screws connected with an endless chain
and actuated by a hand wheel. The pressure of this plate closes up the
bags hermetically. Then, the feed cock being opened, the liquid flows
into all the bags, deposits therein what it holds in suspension, and the
clarified product flows to the inclined bottom of the filter and from
thence to the exterior.

[Illustration: CHENOT'S ECONOMIC FILTER PRESS.]

The apparatus may be supplied either through an upper reservoir, a juice
elevator, or a pump. The discharge is proportional to the square root
of the pressure. When the bags are full of residuum, the feed cock is
closed, the filter is unscrewed, and the bags and frames are taken out.
With fresh bags and the same frames, it is possible to at once set the
apparatus in operation again.

Before the filter is taken apart, the residuum may be exhausted by
washing it either with water or steam, or by pressure. To effect the
operation by pressure, the pieces of wood or metal are removed, the
mouths are closed by making a fold in the top of the bags, and the
latter are then put back into the apparatus or into an ordinary press
and submitted to another squeezing.

To render the maneuvering of it easier, the apparatus has been given a
horizontal position.--_Revue Industrielle_.

[American Engineer]

STEEL CHAINS WITHOUT WELDING.

We take the following description, together with the illustrations, of
a method and machine for making steel chain without welding, from our
valued contemporary, _Le Genie Civil_, of Paris:

When we regard an ordinary oval-linked chain endwise, it presents itself
in the form of a metal cross, and it was this that gave the cue to M.
Oury, of the Government Arsenals, to construct chain without welding. By
a series of matrices and punches, etc., he contrives, with small loss of
metal, to model a chain out of cross-shaped steel bar.

Steel is the better material for such usage, from its homogeneity, both
as to composition and strength.

Referring to the plate below, Figs. 1 to 10 explain the successive steps
from the bar to the finished chain.

Fig. 1 shows in plan and section the steel bar, whose length may be some
40 feet, and which would make a chain say 50 feet long. The shape of the
bar presents no difficulties in the way of rolling.

Figs. 2 and 3 give, in side elevations of the two faces and sections,
the first rough form of the links. These first begin to take the
exterior shape with the rounding of the angles.

The operations following, represented by Figs. 4 and 5, is the piercing
of the center of the links, which can later be furnished with a stay for
such chains as require special strength. The point now is to detach the
links, which is accomplished by oblique piercings, as shown in Fig. 6.
In the operation represented by Fig. 7, the oval shape is imparted to
the link, and the operation finishes as shown in Fig. 8.

Actually, the links are circular and separate. This separation is
retarded as much as possible, for it is plain that it is easier
to operate a rigid bar than a chain, above all when the operation
necessitates its being pushed forward.

By means of a good system of heating, analogous to that employed on the
large parts entering into ship construction, it is hoped to perform a
major part of the operations, of which we have given but an idea, at a
single heat.

[Illustration: MACHINE FOR MAKING CHAIN WITHOUT WELDING.]

These operations require work on both faces alternately--this presents
no difficulties; but what appears to us most difficult to realize is
_continuous work_, the bar passing through several machines which
successively impress upon it the steps of progress toward the finished
chain. If the machines are end on to each other in a direct line, there
will necessarily be a fixed place for each tool; the rough cut chain
must accurately reach the point where another tool is ready to continue
the modeling. This appears to us practically impossible, the more so as
the elongation which the bar takes at each stamp varies with its initial
diameter.

What is more admissible is that with one heat and in the same machine an
operation could be performed on the two faces perpendicularly. The bar
could then be taken from one furnace and put in another immediately,
to pass at once to another machine to again undergo the operations
following. The work could then be done rapidly, submitting the bar to
several heats.

A few words on the tools as they exist.

The most important principle to note, and on which the different
machines employed are designed, is this: The punches or matrices acting
on the chain at its different points of progress are put in motion by
spiral springs worked by means of tappets or cams distributed over the
circumference of a cylinder, having a rotary movement imparted to it by
pulleys and belts.

The figures on our plate show with sufficient clearness the working of
one of these machines. It will be seen that the bar traverses through
and through the machine for stamping, and that it can be disengaged for
a reheating before passing to subsequent operations.

The bog peat of Mexico is now being used on a considerable scale as fuel
for locomotives, stationary engines, smelting purposes, smiths' fires,
and househould use. The peat is mixed with a proper proportion of
bitumen, and is said not only to burn freely, and without smoke in much
quantity, but to give a higher dynamic equivalent of heat than the same
amount of wood.

THE BITTER SUBSTANCE OF HOPS.

[Footnote: _The Brewers' Guardian_, from the _Zeit. f. d. gesammte
Brauwesen_.]

By DR. H. BUNGENER.

Little that is definite is known of the substance or substances to
which the hop owes its bitterness. Lermer has succeeded, it is true, in
separating from hops a crystallized colorless substance, insoluble in
water, an alkaline solution of which has a marked bitter flavor, and
which easily changes on exposure to the air, assuming a resinous form.
According to Lermer, the formula of this substance is C_{32}H_{50}O_{7};
it possesses the properties of a weak acid and forms a characteristic
copper salt, which is soluble in ether. This hop bitter is, however,
produced from the hop by a very roundabout process, by treatment of the
extract with alkalies; it is not therefore regarded by many as present
in this form in the hop, and they hold that it is only produced by
the action of the alkalies. On the other hand, however, Etti, by a
complicated extracting process, but without using an alkali, succeeded
in producing a bitter substance from hops, which is, however, soluble in
water.

Several experiments convinced me that there really existed in hops a
crystallizable substance, insoluble in water, the alcoholic and alkaline
solution of which had a bitter flavor, in short, which possessed all
the properties of Lermer's hop bitter acid. Petroleum ether is the best
practical solvent in use for its isolation, as it does not dissolve
the majority of the remaining constituents of the hop, especially the
hop-resin, which they contain in considerable quantity. Still, the
extraction of hop-bitter acid from hops is a troublesome and thankless
job, the petroleum ether taking up certain substances which add greatly
to the difficulty of purifying the crystals. On the other hand, we can
readily and quickly attain our object, if we employ for our original
material fresh lupuline from unsulphured hops.

The following process has furnished me the best results:

The lupuline is first freed from gross impurities (hop-seed leaves,
etc.), and then covered with petroleum ether boiling at a low
temperature (40° to 70°) in stoppered flasks. The mixture is shaken up
from time to time. After twenty-four hours, by means of a Zullowsky
filter immersed in the mass, and with the aid of a suction-pump, the
dark brown solution is drawn off; then fresh ether is poured on to the
lupuline, and it is allowed to stand for another twenty-four hours.
After this process has been three times repeated, nearly everything the
petroleum will dissolve has probably been extracted. The solutions are
put together, and the petroleum ether distilled off _in vacuo_ at a low
temperature, until there remains in the flask a dark brown sirup, which
on cooling solidifies into a crystalline mass. This is pulverized and
turned on to a filter composed of a large funnel, in which a smaller
funnel covered with muslin is inserted. With the aid of a suction-pump,
the greater portion of the thick, crude solution can be filtered
through. There remains on the filter a highly colored crystalline
"cake," which should be pulverized with a small quantity of petroleum
ether and again filtered. After this operation has been repeated three
or four times, we obtain an almost colorless mass, consisting of
hop-bitter acid, contaminated by small quantities of a fatty substance,
and a substance which I could not isolate, and which I had at first
great trouble in separating from the hop-bitter acid.

If we do not wish to utilize this crude substance at once, it will be
necessary to melt it in the water bath and pour it into a bottle under
close seal, where it will at once crystallize and solidify. If it
remains exposed to the atmosphere, it will soon become sticky and
turn partly into resin. Six kilos of lupuline, which included a large
proportion of sand, furnished 400 grammes of crude hop-bitter acid. The
first experiments in crystallization with petroleum ether gave poor
results; it is difficult to produce the acid pure in large quantities
by this process, as a small quantity of the above substance obstinately
clings to it, and it readily assumes a non-crystallizable form. Our
object is more readily attained if we crystallize it once from alcohol,
for which purpose we dissolve it in a little lukewarm alcohol, then
quickly cool the solution; flakes of a fatty substance will be
separated, which are removed by filtration with the aid of a
suction-pump. Then we throw a few small crystals of the acid into the
solution, and after a short time crystallization commences. As soon as
it appears to be ended, the mother solution is removed with the aid of a
platinum cone, and the crystals washed with a little cold alcohol. The
alcoholic mother solution, which still contains the chief part of the
bitter acid, must be quickly evaporated, and the residue consigned to
a flask. The acid crystallized from the alcohol is then recrystallized
several times from petroleum-ether. In order to quickly dissolve the
bitter substance, it should be carefully melted in a flask, and double
its volume of ether gradually added; on its cooling, we obtain beautiful
prismatic crystals, which attain a length of 1 cm., and become perfectly
pure after four or five crystallizations. The mother solutions must be
speedily evaporated if we still wish to obtain crystals; after a time
they will only furnish a resinous residue.

The hop-bitter acid melts at 92° to 93°. It is easily soluble in
alcohol, ether, benzol, chloroform, sulphide of carbon, and vinegar; to
a lesser extent in cold petroleum ether, and not at all in water.

In the analysis I obtained figures which correspond best with those
calculated from the formula C_{25}H_{35}O_{4}.

                                     Obtained.
  Calculated.  ------------------------^-----------------------
  -----^-----  2. Crystal. 3. Crystal.  5. Crystal. 6. Crystal.
        p.c.   p.c.    p.c.     p.c.   p.c.    p.c.    p.c.
    C  75.19   74.79   74.83    74.9   75.04   75.05   75.07
    H   8.77    8.97    8.90     8.85   8.87    8.83    8.80
    O  16.04

If we shake up the ether solution of bitter substance with an aqueous
solution of acetate of copper, the ether will assume a green color, and
gradually deposits a green crystalline powder, a cupreous combination
of the bitter acid. It is difficult to obtain in a pure state, as the
solutions are readily subject to slight decomposition, accompanied by a
small deposit of copper oxide. This combination is readily soluble in
alcohol, to a lesser extent in ether, and is insoluble in water.

In the course of analysis, I obtained the following figures:

   C    69.4 per cent.        69.3  per cent.
   H     7.95     "            7.98     "
   Cu    7.20     "            7.18     "

If we suppose that the copper combines with two molecules of hop-bitter
acid, by the decomposition of one of its atoms, H, we obtain the formula
C_{50}H_{68}O_{8}Cu. This combination will contain 69.87 per cent. C,
7.91 per cent. H, and 7.33 per cent. Cu. The figures obtained do not
perfectly coincide with those calculated; it is nevertheless probable
that the formula is correct, and the combined substance analyzed was not
perfectly true.

I have already referred to the fact that solutions of hop-bitter acid,
if left standing too long, assume a yellow color, and on evaporation
leave only a yellow resinous residue. This, as its reaction shows,
evinces a complete analogy with the crystallized acid. The dark-colored
mother solution, from which the crystalline cakes of bitter acid are
obtained, contains a large proportion of this resinous compound, which
can be isolated by treatment with a weak soda-lye; this substance, like
the crystallized acid, is soluble in alkalies, and can be precipitated
from an alkaline solution by an acid. Old hops furnish far less
crystallizable acid than new hops; from some samples I have been able to
obtain only a few crystals; the remainder had been transformed into the
resinous modification.

If pure hop-bitter acid be pulverized and exposed to the atmosphere, it
soon turns yellow and the surface assumes a resinous consistency. At
the same time, a more pronounced odor of fatty acids and aldehydes is
apparent. Still more rapidly will this oxidation occur if a thin layer
of an alcoholic solution of the acid is allowed to evaporate in the air.
On the other hand, we can allow hop-oil to stand for days without its
odor being perceptibly changed; it appears to me more than probable that
the peculiar smell of old hops is due far more to the oxidation of the
bitter substance than to the oxidation of oil.

Hop-bitter acid appears to possess the character of an aldehyde and of
a weak acid; for the present I am not in a position to state its
constitution more clearly. Most of the oxidizing processes have an
energetic effect on it, forming also considerable quantities of
valerianic acid.

The question as to whether the hop owes chiefly to this acid and its
resinous modifications the property of imparting a pronounced bitter
flavor to a solution, I must for the present leave unanswered. The acid
and its isomer are both insoluble in water; they are, on the other hand,
very readily dissolved in hop oil; they also furnish a tolerably bitter
solution, if boiled for a long time in water, probably on their account
of their gradual decomposition. I will not for the present go further
into the subject, as I hope soon to be in a position to give more
definite information.

ST. PAUL'S VICARAGE, FOREST HILL, KENT.

This vicarage, for the Rev. Frank Jones, has recently been completed
from the designs of Mr. E.W. Mountford, A.R.I.B.A.; of 22 Buckingham
Street, Strand, W. C., and Mr. H. D. Appleton, A.R.I.B.A., of the Wool
Exchange, Coleman Street, E. C., who were the joint architects. The
builder was Mr. William Robinson, of Lower Tooting, S. W. The walls are
of yellow stock bricks, with red brick arches, quoins, etc., the gables
being hung with Kentish tiles and the roofs covered with Broseley tiles.
The internal joinery is of pitch pine.

[Illustration: ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM ROAD.]

[Illustration: ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM GARDEN.]

The illustrations are from drawings by Mr. J. Stonier.--_The Architect_.

SOME ECONOMICAL PROCESSES CONNECTED WITH THE CLOTHWORKING INDUSTRY.

[Footnote: Read before the Society of Arts, London, May, 1884.]

By Dr. WILLIAM RAMSAY, Professor of Chemistry at University College,
Bristol.

In this present age of scientific and technical activity, there is
one branch which has, I think, been the subject of an article in the
_Quarterly Journal of Science_. It is one which deserves attention. It
was there termed "The Investigation of Residual Phenomena," and I can
conceive no better title to express the idea. The investigator who
first explores an unknown region is content if he can in some measure
delineate its grand features--its rivers, its mountain chains, its
plains; if he be a geologist, he attempts no more than broadly to
observe its most important rock formations; if a botanist, its more
striking forms of vegetation. So with the scientific investigator. The
chemist or physicist who discovers a new law seldom succeeds in doing
more than testing its general accuracy by experiments; it is reserved
for his successors to note the divergence between his broad and sweeping
generalization and particular instances which do not quite accord with
it. So it was with Boyle's law that the volume of a gas varies in
inverse ratio to the pressure to which it is exposed; so it is with the
Darwinian theory, inasmuch as deterioration and degeneration play a part
which was, perhaps, at first overlooked; and similar instances may be
found in almost all pure sciences.

I conceive that the parallel from the technical point of view is a
double one. For just as every technical process cannot be considered
to be beyond improvement, there is always scope for technical
investigation; but the true residual phenomena of which I would speak
to-night are waste products. There is, I imagine, no manufacture in
which every substance produced meets with a market. Some products are
always allowed to run to waste, yet it is evident that every effort
consistent with economy should be made to prevent such waste; and it has
been frequently found that an attempt in this direction, though at first
unsuccessful, has finally been worked into such a form as to remunerate
the manufacturer.

It is my purpose to-night to bring under your notice methods by which
saving can be effected in the cloth industry. I am aware that these
methods have not much claim to novelty; but I also know that there are,
unfortunately, few works where they are practiced.

The first of these relates to the saving and utilization of the soap
used in wool scouring and milling. It is, perhaps, hardly necessary to
explain that woolen goods are scoured by being run between rollers,
after passing through a bath of soap, and this is continued for several
hours, the cloth being repeatedly moistened with the lye, and repeatedly
wrung out by the rollers. The process is analogous to ordinary washing;
the soap dissolves the greasy film adhering to the fibers, and the
"dirt" mechanically retained is thus loosened, and washed away. Now, in
order to dissolve this greasy matter, a considerable amount of soap must
be employed; and in the course of purification of the fabric, not merely
what may be characterized as "dirt" is removed, but also short fibers,
and various dye-stuffs with which the fabric has been dyed, many of
which are partially soluble in alkaline water; moreover, it invariably
happens that some dye does not combine with the fiber and mordant, thus
becoming fixed, but merely incrusts the fiber; hence this portion is
washed off when the retaining film of grease is removed from the fiber.
The suds, therefore, after fulfilling this purpose, are no longer a pure
solution of soap, but contain many foreign matters; and the problem is
so to treat these suds as to recover the fat in some condition available
for re-conversion into soap.

For this purpose wooden runnels are placed beneath the rollers, through
which the cloth passes in the scouring machine, so as to collect the
suds after they have been spent. These runnels lead to a wooden pipe or
runnel, which receives the spent suds from all the scouring machines,
and the whole of the waste, instead of being let off into the stream,
polluting it, delivers into a tank or trough, which may also be
constructed of wood, but, as it has to withstand the action of acid, is
better lined with lead. This tank is necessarily proportioned in size
to the number of scouring machines and the quantity of spent suds to
be treated. When a sufficient quantity has collected, oil of vitriol,
diluted with twice its bulk of water, is added, one workman pouring it
in gradually while another stirs the contents of the tank vigorously. At
short intervals, the liquid is tested by means of litmus paper, and
when it shows a faint acid reaction, by turning the blue paper red, the
addition of acid is stopped. The acid has then combined with the alkali
of the soap, while the fatty acids formerly in combination with the
alkali are liberated, and float to the surface of the liquid, carrying
with them the impurities in the shape of short fibers and dye stuffs;
the sand and heavier impurity, should any be present, sinks to the
bottom.

After standing for some hours, the separation is complete. In order to
separate the two layers, the tank is provided with an exit in the side,
near the bottom, closed by a sluice or valve. This valve is opened, and
the watery portion is allowed to escape into a sand filter bed.

The filter serves to retain any solid impurities which may still remain
suspended in the water; but it will be found that the escaping water is
nearly pure.

The dark brown fatty acid is mixed with a large amount of impurity, such
as short wool fibers, burrs, sand, and dye stuffs washed from the wool.
To remove water more completely, the semi-fluid mass is pumped from the
tank, and delivered into hair-cloth filters; the liquid which drains
from these bags finds its ways to the sand filters joining the drainage
which formerly passed out from the tank through the sluice. After being
turned over in the filter several times, the residue is transferred to
canvas sacks. These sacks are placed in a filter press, where they are
exposed to pressure while heated to a temperature sufficient to melt
the fat. The solid impurities remain in the bags, while the fatty acids
escape, and are received in a barrel or tank for the purpose. The fatty
acids, when cold, are of a deep brown color, and of the consistency
of butter. The residue is kept, and the method of treating it for the
recovery of indigo will afterward be described.

The fatty acids are now ready for conversion into soap. It may here be
remarked that, on distillation, they yield a nearly white fatty mass,
which, when treated with soda-lye, is capable of yielding a perfectly
white soap. But, for the clothworker's purpose, this purification is
unnecessary.

The conversion into soap is a very simple matter. As the fats are
acids--a mixture of palmitic, oleic, and stearic acids--and not the
glycerine salts of these acids, like ordinary fats, soap is made by
causing them directly to unite with caustic soda. The fats are melted
in a copper, by means of a steam-jacket, or coil of steam-pipe in the
copper, and the soda-lye is run in until complete union has taken place.
The exact point of neutralization can easily be found by taking out
a small sample after stirring, and dissolving it in some methylated
spirits. A few drops of alcoholic tincture of phenol-phthalein are then
added, and as soon as a faint red color appears, addition of soda is
stopped. This shows that the fatty acids have been over-saturated.
Addition of a little more fat renders them perfectly neutral, and the
soap is then ladled out into wooden moulds, lined with loose sheets of
zinc.

The resulting soap is of a brown color, but is perfectly adapted for the
purpose of wool-scouring. It should here be mentioned that, in practice,
the soap is always made somewhat alkaline; in point of fact, it contains
about 2 per cent. of free alkali. This is found to assist in scouring; I
presume that the free alkali forms a soap with the oil added to the wool
during spinning, and if no free alkali be present, this oil would not be
so thoroughly removed.

It will be noticed that in this simple method of soap-making, there is
no salting out to separate the true soap from the watery solution of
glycerine, for no glycerine is present. The apparatus may be of the
simplest nature, and on any required scale, proportionate to the size of
the mill. It is a process which requires no specially skilled labor; in
any works some hand may be told off to conduct the process as occasion
requires; and as a very large proportion of the fatty matter is
recovered, the soap-bill is reduced to a very small fraction of the
amount which would be paid were recovery not practiced. And lastly, the
streams are not polluted; the only waste is a little sulphate of soda,
which can hardly be regarded as a nuisance, inasmuch as it is a not
unfrequent constituent of many natural waters.

Let us now return to the solid matter from which the fatty acids have
been removed by pressure. This brown, earthly-looking cake consists of
vegetable impurity washed off from the cloth, of short fibers, and of
various dye stuffs. It is divided into two lots: That which contains
indigo, and that which contains none, or which contains too small a
quantity for profitable extraction. And it may here be remarked, that it
is advisable to collect the suds from cloth dyed with indigo separate
from that to dye which no indigo has been employed. The residue from
indigo-dyed cloth has always a more or less blue shade, and if much
indigo is present, the well-known copper-color is evident. Of course,
the amount of indigo must greatly vary, but it may rise to 8 or 10 per
cent. of the total weight of the refuse.

To recover the indigo from this refuse, the somewhat hard cakes are
broken up, placed in a tank, and allowed to steep in water. When quite
disintegrated, they are transferred to another tank--a barrel may be
used for small quantities--and thus this refuse is exposed to the
reducing action of copperas and lime. The indigo is converted into
indigo-white, and is rendered soluble, and it oxidizes on the surface,
forming a layer of blue froth on the top of the liquid, while the
remainder of the impurities sinks. This process of reduction may last
for twenty-four hours, and is helped by frequent stirring.

The indigo scum is preserved, and placed in filter cloths, where it is
thoroughly washed with water two or three times. The residue which has
sunk to the bottom is removed, dried, and forms a valuable manure,
owing to the amount of the nitrogen which it contains. Its value may be
increased by addition of weak vitriol, which exercises a decomposing
action on the nitrogenous matter, forming with it sulphate of ammonia.
The original residue from the filter-press, if it does not contain
indigo, may be at once put to similar use.

In large works, which dye their own goods, it is well known that the
"fermentation vat" is in general use for indigo-dyeing. But this vat
requires constant superintendence, and must be kept in continual action;
besides, it is successful only on a comparatively large scale. And,
moreover, it requires skilled labor. Small works, or works in which
dyeing is only occasionally practiced, find it more convenient to use
Schützenberger and Lalande's process. Although this process is well
known, a short description of it may not here be out of place.

The process depends on the reduction of indigo to indigo-white, or
soluble indigo, by means of hyposulphite, or, as it is generally termed
to avoid confusion with antichlore, rightly named thiosulphate of soda,
hydrosulphite of soda. The formula of this substance is NaHSO_{2}, as
distinguished from what is commonly known as hyposulphite of soda,
Na_{2}S_{2}O_{3}. It is produced by the action of zinc-dust on the acid
sulphite of soda. The zinc may be supposed to remove oxygen from the
acid sulphite, NaHSO_{3}, giving hyposulphite, NaHS0_{2}. The reduction
of the acid sulphite is best performed in a cask, which can be closed at
the top, so as to avoid entrance of air. The acid sulphite of soda, at a
strength of 50 or 60 Twaddell (specific gravity 1.26 to 1.3), is placed
in the cask, and zinc-dust is added, with frequent stirring. The liquid
is then mixed with milk of lime, and after again thoroughly stirring,
the liquid is allowed to settle, and the clear is decanted into the
dyeing-copper. The indigo, in the frothy state in which it is skimmed
from the purifying barrels or tanks, is then added, with sufficient lime
to dissolve it when it has been reduced. It is heated gently by a steam
coil, to about 90° Fahr., and the goods are dyed in it. The colors
obtained by means of this indigo are light in shade, and the goods must
be dipped several times if dark shades are required. But it is found
better in practice not to attempt to dye dark shades by this process;
the ordinary indigo-vat is better adapted for such work. The object of
not wasting indigo is sufficiently attained by employing it for the
purpose to which it is best adapted. Of course the recovered indigo may
be used in the ordinary manner. I merely mention the most convenient way
of disposing of it in works where only a small quantity is recovered,
and which do not practice dyeing on an extensive scale.

I have now to ask you to turn to a different subject, namely, the
scouring of wool, not by the usual agent, water, but by a liquid,
bisulphide of carbon, made by the action of sulphur vapor on red hot
coke or charcoal.

This, again, is not wholly a new process, for various attempts have
been made to dissolve out the yolk, or _suint_, or greasy matter from
unwashed wool, as it comes from the back of the sheep. Fusel oil
has been patented for this purpose. Carbon disulphide has also been
patented, but, as will afterward be shown, the old method of removing it
from the wool injured the color and quality of the fiber, so as to make
the application of this scouring agent a failure.

Wool in its unwashed state contains a considerable proportion of what is
termed _suint_. This consists of the fatty matter exuded as perspiration
from the sheep, along with, or in some form of combination with, potash
derived from the grass on which the sheep feed. _Suint_ was first
investigated by Vauquelin. He obtained it by evaporating, after
filtration, the water in which raw fleeces had been washed. The residue
is of a brown color, and has a saline, bitter taste. On addition of an
acid to its solution in water, it coagulates, and a fatty matter rises
to the surface. It is, in fact, a potash soap, to a great extent
containing carbonate and acetate of potash, along with chloride of
potassium and lime, probably in combination also with fatty acids. It is
usually mixed with sand and carbonate of lime.

In 1828, M. Chevreul, who is still alive in Paris, although nearly a
century old, published an analysis of merino wool. It consisted of:

                                 Per cent.
  Pure wool                        31.23
  Soluble _suint_                  32.74
  Insoluble                         8.57
  Earthy matter                    27.46
                                  100.00

It is easily seen that _suint_ forms a very important constituent of raw
wool. Its proportion varies, of course, according to the nature of the
pasture on which the sheep are fed, the climate, etc. Wool from Buenos
Ayres, for example, contains much less than that analyzed by M.
Chevreul; its amount is only 12 per cent. of the weight of the raw wool.

This _suint_ contains always about 52 per cent. of residue when ignited.
The composition of this residue is:

                                 Per cent.
  Carbonate of potash              86.78
  Chloride of potassium             6.18
  Sulphate of potash                2.83
  Silica, alumina, etc.             4.21
                                  100.00

In 1859, MM. Maumene and Rogelet patented the use of the water in
which wool has been washed as a source of potash, and at present the
extraction of potash from _suint_ is practiced in France on a large
scale. The wool is washed in a systematic manner, in casks, with cold
water, which runs out of the last cask with specific gravity 1.1. These
washings are evaporated to dryness, and the residue is calcined in iron
retorts, the gas evolved being used for illuminating purposes. The
remaining cinder, consisting of a mixture of charcoal and carbonate of
potash, is treated with water, whereby the latter is dissolved out.
The residue left on evaporation of this water consists largely--almost
entirely--of white carbonate of potash. At present there are works at
Rheims, Elboeuf, Fourmier, and Vervier, which yield about 1,000 tons of
carbonate of potash annually. Now, only 15,000 tons are made per annum
by Leblanc's process. In 1868, 62,000 tons of wool were imported into
Britain from Australia alone, and from this 7,000 to 8,000 tons of
carbonate of potash might have been recovered, the value of which is
£260,000. Yet it was all wasted! And this estimate does not include the
fats of the _suint_, which are worth an even greater sum.

Now, it is evident that there is here a profitable source of economy. So
far as I am aware, no work in this country saves its washings. The water
all goes to pollute the nearest river.

The use of carbon disulphide has again been introduced, and it is to be
hoped with better success, for methods have been devised whereby the
wool is not injured by it, but is even rendered better than when scoured
by the old process of washing with carbonate of soda and water, or by
soap. The process is due to Mr. Thomas J. Mullings. Briefly described,
it consists in exposing the wool, placed in a hydro-extractor, to the
action of bisulphide of carbon; the machine is then made to revolve, and
the excess of solvent is expelled, carrying with it the fatty matters;
the solvent finds its way into a tank, from which it flows into a still,
heated with steam; the carbon disulphide, which boils at a very low
temperature, distills over, and is again ready for use, while the
residue in the still consists of _suint_ washed from the wool. To
remove the last trace of carbon disulphide from the wool in the
hydro-extractor, cold water is admitted, and when the wool is soaked,
the machine again revolves. On expulsion of the water, the wool is ready
for washing in the ordinary machines, but with cold water only instead
of hot soapsuds.

The distinguishing features of Mr. Mullings' process are, method by
which loss of carbon disulphide is avoided, and the extraction of
that solvent by means of cold water. The apparatus consists of a
hydro-extractor or centrifugal machine of special construction, fitted
with a bell-shaped cover, which can be lifted into and out of position
by means of a weighted lever. The rim of this cover fits into an annular
cup filled with water, which surrounds the top of the machine, forming
an effective seal or joint. Upon the spindle of this machine is
suspended, as in ordinary forms of the hydro-extractor, a perforated
basket, and in this basket is placed the wool to be treated. The cover
being closed, the carbon disulphide is admitted, and passing through the
wool, the greasy matter is dissolved, and along with the solvent enters
a reservoir. The machine is now set in motion, and the bulk of the
solvent is drawn off. Cold water is then admitted, and the machine being
again caused to rotate, the whole of the bisulphide is expelled. It is
a curious fact that, although wool soaks remarkably easily with carbon
disulphide, and at once becomes wet, cold water expels and replaces
almost all that liquid. This operation takes about twenty minutes, and
at one operation about 1½ cwt. of raw wool may be treated. The wool is
then washed in suitable washing machines of the ordinary type, but with
cold water, no soap or alkali being employed. The bisulphide of carbon,
mixed with water, flows into a reservoir, provided with diaphragms to
prevent splashing, and consequent loss by evaporation. From its gravity
it sinks, forming a layer below the water; it is then separated and
recovered by distillation, and may be used in subsequent operations.

The point in which this process differs from the old and unsuccessful
ones formerly tried, is in the expulsion of the carbon disulphide. It
was imagined that it was necessary to expel it by means of heat or
steam. Now, when wool moist with bisulphide is heated, it invariably
turns yellow. No heat must, therefore, be employed. As already remarked,
the solvent is expelled with cold water.

The residue, after distillation of the carbon disulphide, is a grayish
colored, very viscous oily matter, still retaining a little bisulphide,
as may be perceived from the smell. It has not the composition of
ordinary _suint_, inasmuch as it contains no carbonate of potash, and
indeed little mineral matter of any kind. A sample which I analyzed
lost in drying 36.2 per cent., the loss consisting of water and carbon
disulphide. It gave a residue on ignition amounting only to 1.6 per
cent. of the original fatty matter, or 2.5 per cent. of the dried fat.
The oil appears, from some experiments which I made, to be a mixture of
a glycerine salt and a cholesterine salt of fatty acids. It distills
without much decomposition, giving a brown-yellow oil, which fluoresces
strongly, and has a somewhat pungent smell. The molecular weight was
determined by saponification with alcoholic potash, and subsequent
titration of the excess of potash employed. This was found to equal
546.3. This would correspond to a mixture of 18.7 parts of stearate,
palmitate, and oleate of glycerine, with 81.3 parts of the same acids
combined with cholesteryl. But this is largely conjecture. The
boiling point of the oil is high, much above the range of a mercurial
thermometer, so that it is difficult to gain an insight into its
composition.

An objection which has been raised to this process is that the use of
such an easily inflammable substance as bisulphide of carbon is attended
by great risk of fire. Were the bisulphide to be exposed to free air,
there might be force in this objection; but there is no reason why it
should ever be removed from under a layer of water. The apparatus, to
make all safe, should not be under the same roof as the mill; and no
open fire need be used in the building set apart for it. It is easy to
rotate the centrifugal machine by a belt from the mill, but better by a
small engine attached, the power for which can be conducted by a small
steam-pipe, and the distillation of the bisulphide can also be conducted
without danger by the use of steam, as its boiling point is a very low
one. The question may be naturally asked, "How do the wool and fabric
made from the wool scoured by this process, compare with that scoured in
the usual way?" To answer this question I may refer to a test made by
Messrs. Isaac Holden & Co., at their works at Roubaix. A sample of wool
was divided into two portions, one of which was scoured by the usual
method, and the other by the turbine or Mullings' process. Skilled
workers then span each sample to as fine a thread as possible. Now
the thinness to which a wool can be spun is evidence of its power of
cohesion--in other words, its strength. The weight of 1,000 meters of
the wool cleaned by the new process bore to that scoured by the old
process the proportion of 1,015 to 1,085, showing that a considerably
finer thread had been produced. And in total quantity, 67.53 kilos.
of the former corresponded to 71.77 kilos. of the latter, showing
a proportionately less waste. Such fine yarn had never before been
obtained from similar wool. The yarn of the soap-washed wool could not
be spun, for it could not withstand the strain; whereas, that scoured by
the new process gave an admirable thread.

Another test to which it was subjected may be cited. It is the custom in
France, before the wool is scoured, to put it through a sorting process,
by which all the short lengths are weeded out. On a quantity exceeding
11,000 kilogrammes, half of which was scoured by the turbine process,
and half by the ordinary process, the former in scouring lost in weight
2 per cent. less than the latter, although the short length extracted
from the moiety thus treated weighed only 10 kilogrammes, while that
taken from the other weighed over 150 kilogrammes. This saving, even
with the unequal treatment, amounted in value to from 30 to 40 centimes
per kilogramme.

In order that the importance of this application may be realized, I
shall conclude with some figures:

The raw wool imported into England, in the year 1882, amounted to
1,487,169 bales, its total value being about £22,000,000. The cost of
washing this wool by the old process, with carbonate of soda, amounts to
about ½d. per lb. of the raw material. The cost for the total quantity
of wool imported is at least £1,214,000. But it is customary to wash
wool with soap, especially for the combing trade, and the cost is then
about 1d. per lb. The cost of scouring by the new process is about £1
5s. per ton, or 0.13d. per lb. Taking the least favorable comparison,
were all the imported wool (home-grown wool is here left out of the
calculation, for want of sufficient returns) cleansed by the turbine
process, the actual saving would be £1,214,500 _minus_ £315,700, or
nearly £900,000 per annum.

It is thus seen that there is room for a very important economy in
the treatment of wool. I have endeavored to show how economy may be
practiced in scouring by the old process with soap, and how one dye
stuff may be profitably recovered. It is to be hoped that means of
extracting other dyes from the residue may soon follow. Unless the
process were too costly to repay the trouble of extraction, it would
be well worth practicing; for it would not merely be a solution of the
problem of how to avoid waste, but would at the same time prevent the
pollution of our streams, now, unfortunately, only too rarely pellucid;
and were the last process to have as successful a future as I hope it
may have, a very important saving of expense would result, and a large
quantity of valuable fatty matter would no longer be thrown away.

[Illustration: SUGGESTIONS IN DECORATIVE ART.--DESIGNS FOR IRON GATES.]

COAL AND ITS USES.

[Footnote: From a paper lately read before the Association of Foremen
Engineers.]

By JAMES PYKE.

The records from which geologists draw their information can scarcely be
compared to written or printed histories. There are, however, nations
of whom no written account exists, who perhaps never had any written
history, but about whom we are still able to gather from other sources
a vast amount of information. Their houses, their monuments, their
weapons, and their tools have survived, and these tell us the kind of
life, the state of civilization, and the skill of the men to whom they
belonged; from the contents of their tombs we learn what manner of men
they were physically; sometimes a sudden change in the appointments and
belongings of the folk indicates that tribes which had for a long time
inhabited a district were driven out and replaced by a new race. Thus,
then, from waifs and strays we can piece together a fairly connected
account of the events of a period long antecedent to any written
history.

The investigations of Dr. Schliemann on the supposed site of the city of
Troy furnish a good example of this method of research. He found lying,
one on the top of another, traces of the existence of five successive
communities of men, differing in customs and social development, and was
able to establish the fact that some of the cities had been destroyed by
fire, and that later on other towns had grown up over the buried remains
of the earlier settlements. The lowest layers were, of course, the
oldest, and the position of each layer in the pile gives its date, not
in years, but with regard to the layers above and below it.

Now, from time immemorial nature has been at work building up monuments
and providing tombs which tell us what were the events going on,
and what kind of inhabitants the earth had long before man made his
appearance on its surface. The monuments are the rocks which compose the
ground under our feet, and these, like many ancient monuments of human
construction, are the tombs of the creatures that lived while they were
being built.

Many facts testify that the earth's crust did not come into existence
exactly as we find it now, but that its rocks have been built up by the
slow action of natural agencies. These rocks constantly inclose the
remains of plants and animals, and as it is evident that neither plant
nor animal could have lived in the heart of a solid rock, this fact
shows that the rock must in some way have gathered round the remains
that are now found in it. Again, many of these remains, or fossils,
belonged to animals that lived in water, the larger part, indeed, to
marine creatures. This indicates that the rock was formed beneath the
sea, and when we examine the way in which the constituents of the rock
are arranged, we frequently find it to correspond exactly with the
manner in which the sand and mud that rivers sweep down into the sea or
lakes are spread out over the bottom of the water. In a pile of rocks
formed in this way it is clear that the lowest is the oldest of all, and
that any one stratum lying above is younger than the one beneath it.
Further, the occurrence of rocks inland containing marine fossils far
above the sea level shows that the sea and land have changed places.
When, again, we find that the fossils of one group of rocks differ
entirely from those of a group lying above them, we learn that one race
of creatures died out and was supplanted by a new assemblage of animal
forms.

These general remarks will, I trust, give some notion of the evidence
which is available for reconstructing the history of those remote
periods with which geology deals, and of the kind of reasoning which the
geologist employs for interpreting the records that are submitted to
him.

We will now briefly examine, by aid of these methods, the group of rocks
in which coal occurs in Great Britain, and see how far we can read the
story they have to tell.

The group with which we have to deal is called the carboniferous or
coal bearing system, and it includes four classes of rocks, viz.: 1,
sandstone; 2, shale or bind; 3, limestone; 4, coal and underclay.

We will take the sandstones and shales first. They are grains of sand
known to mineralogists as quartz, and consisting of a substance called
silica by chemists. The grains of sand are bound together by a cement
which in some few cases is identical in composition with themselves, and
consists of pure silica, but usually is a mixture of sandy, clayey, and
other substances. The shales are made up very largely of clay, mixed,
however, usually with sand and other substances, forming a conglomerate.
Both sandstones and shales are divided into layers or beds, and are said
to be stratified. It is this stratified or bedded structure that gives
us the first clew to the way in which these rocks were formed. Rivers
are constantly carrying down sand and mud into the sea or lakes, and
when their flow is slackened on entering the still water the materials
they bring down with them sink and are spread out in layers over the
bottom. The structure of the sandstones and shales shows that they were
formed in this way; they often inclose the remains of plants that have
been carried down from land, and occasionally of animals that lived in
the water where they were deposited.

The next we have to consider is limestone, which is mainly made up of a
substance known to chemists as calcium carbonate, or carbonate of lime.

In some districts, especially in volcanic countries, springs occur very
highly charged with carbonate of lime. The warm springs of Matlock are
a case in point; they are probably the last vestige of volcanic action
which was in operation in that neighborhood during carboniferous times.
Limestone is chiefly formed by the agency of small marine creatures of
low organization. By the aid of these animals the carbonate of lime is
brought back to a solid form; at their death their hard parts fall to
the bottom and accumulate in a mass of pure limestone, which afterward
becomes solidified into limestone rock.

The information that limestone gives us is this:

When we find, as is often the case, a mass of limestone hundreds of feet
thick, and composed of little else but carbonate of lime, we know that
the spot where it occurs was, at the time it was formed, far out at sea,
covered by the clear water of mid ocean; and when we find that this
limestone grows in certain directions earthy and impure, and that layers
of shale and sandstone, thin at first, but gradually thickening out in
a wedge-shape form, come in between its beds, we know that in those
directions we are traveling toward the shore lines of that sea whence
the water was receiving from time to time supplies of muddy and sandy
sediment.

The next class of rocks are the clays that are found beneath every
bed of coal, and which are known as _underclays_, or _warrant_, or
_spavins_. They vary very much in mineral composition. Sometimes they
are soft clay; sometimes clay mixed with a certain portion of sand; and
sometimes they contain such a large proportion of silicious matters that
they become hard, flinty rock, which many of you know under the name
of _gannister_. But all underclays agree in two points: they are all
unstratified. They differ totally from the shales and sandstones in this
respect, and instead of splitting up readily into thin flakes, they
break up into irregular lumpy masses. And they all contain a very
peculiar vegetable fossil called _Stigmaria_.

This strange fossil was for a long time a sore puzzle to fossil
botanists, and after much discussion the question was fairly solved by
Mr. Binney by the discovery of a tree embedded in the coal measures,
and standing erect just as it grew, with its roots spread out into the
stratum on which it stood. These roots were Stigmaria, and the stuff
into which they penetrated was an underclay. Sir Charles Lyell mentions
an individual sigillaria 72 feet in length found at Newcastle, and a
specimen taken from the Jarrow coal mine was more than 40 feet in length
and 13 feet in diameter near the base. It is not often these trees are
found erect, because the action of water, combined with natural decay,
has generally thrown them down. They are, however, found in very large
numbers in the roof of the coal, evidently having been tossed over, and
lying there flat and squeezed thin by the pressure of the measures that
lie above them.

Lastly, we come to coal itself--a rock which constitutes a small portion
of the whole bulk of the carboniferous deposits, but which may be fairly
looked upon as the most important member of that group, both on account
of its intrinsic value and also from the interest that attaches to its
history. That coal is little else but mineralized vegetable matter is a
point on which there has for a long time been but small doubt. The
more minute investigations of recent years have not only placed this
completely beyond question, but have also enabled us to say what the
plants were which contributed to the formation of coal, and in some
cases even to decide what portions of those plants enter into its
composition. It is a thing so universally admitted on all hands, that I
shall take it for granted you are all perfectly convinced that coal has
been nothing in the world but a great mass of vegetable matter. The only
question is: How were these great masses of vegetable matter brought
together? And you must realize that they were very large masses indeed.
Just to take one instance. The Yorkshire and Derbyshire coal field is
somewhere about 700 to 800 square miles in area, and Lancashire about
200. Well, in both these coal fields you have a great number of beds of
coal that spread over the whole of them with tolerable regularity and
thickness, and very often with scarcely any break whatever. And this is
only a very small portion of what must have been the original sheet of
coal, so that you see we have to account for a mass of vegetable matter
perfectly free from any admixture of sand, mud, or dirt, and laid down
with tolerably uniform thickness over many hundreds of square miles.

At one time it was supposed that coal was formed out of dead trees and
plants which were swept down by rivers into the sea, just in the same
way as shales and sandstones were formed out of mud and sand so swept
down. The fatal objection to this theory, however, is that rivers would
not bring down dead wood alone, but they would bring down sand and mud,
and other matters, and that in the bottom of the sea the dead wood would
be mixed with these matters, and instead of getting a perfectly unmixed
mass of vegetable matter, we should get a mixture of dead plants, sand,
mud, and other things, which would give rise to something like coal, but
something very different, as any one who tries to burn such coal will
soon find out, from really good, pure house coal. So that this theory,
which is generally known as the "drift" theory, was totally inadequate
to account for the facts as we know them.

The other theory was that coal was formed out of plants and trees that
grew on the spot where we now find coal itself. On this supposition it
is easy to account for the absence of foreign admixtures of sand, mud,
and clay in the coal; and we can also understand very much better than
by the aid of the drift theory how the coal had accumulated with such
wonderful uniformity of thickness over such very large areas. This
theory was for some time but poorly received; but after the discovery
of Sir William Logan, that every bed of coal had a bed of underclay
beneath, and the discovery of Mr. Binney, that these underclays were
true soils on which plants had undoubtedly grown, there was no doubt
whatever that this was the real and true explanation of the matter.

I dare say many of you have had occasion to walk across peat bogs.
The peat bog is a great mass of vegetable matter, which is every year
growing thicker and thicker; and underneath it there is almost always a
bed of thin clay, in look very much like the underclays, and this thin
clay is penetrated by the rootlets of the moss forming the peat, exactly
the same way as the underclays of the coal measures are penetrated by
the stigmaria and its rootlets. But you must not suppose that the plants
out of which coal was formed were exactly the same low type of moss
which forms our present peat bogs. However, it is pretty certain that
they were for the most part of a loose, succulent texture, and that they
grew very rapidly indeed.

You will have noticed that there is one step more wanted to make good
this theory of the growth of coal on the spot where we now find it.
The coal is found, as already described, interbedded with shales and
sandstones. These shales and sandstones, as shown, were formed beneath
the water of the sea, and as long as they remained there of course no
plants could grow upon them. The question is, How was the land surface
formed for the growth of plants? It must have been formed in some way or
other by the sea bottom having been raised above the level of the water.
Now, we have distinct proof in many cases that elevation of the sea
bottom and depression of the land is now going on in many parts of the
earth's surface. And, therefore, we shall be assuming nothing beyond the
range of experience if we say that such elevations and depressions went
on during coal measure times. The coal measure times must have been
times during which the same spot was now below the sea, and now dry
land, over and over again. There was a land surface on which plants grew
fast and multiplied rapidly, and as they died fell and accumulated in
a great heap of dead vegetable matter. After a time this layer of
vegetable matter was slowly and gently let down beneath the waters of
the sea--so slowly that the water flowing over it did not, as a rule,
disturb the loose, pasty mass; and then, by the method I have described
to you, shales and sandstones were deposited on the top of this mass
of dead vegetable matter. By their weight they compressed it, and
by certain chemical changes (which we have not time to go into this
evening) this dense mass of vegetable matter became converted into coal.
After a time the shales and sandstones which had been piled above this
stuff, which was to form coal for the future, were again elevated to
form a land surface; upon this another forest sprang up, and by its
decay produced another mass of vegetable matter fit to form coal. This
again was let down below the water, more shales and sandstones were
deposited on the top, and this process went on over and over again till
the whole mass of our present coal measures was formed. You will now see
how it is that trees are so seldom found in an upright position in the
coal beds. As the land went down, they would in very many cases be
toppled over by the water as it flowed against them, or their base would
be rotted, and they would then either fall or be blown over; that is the
reason why in most cases they are found lying flat on the roof of the
coal bed. But in a few cases, when the depression was very gentle and
gradual, the trees were not overthrown, and the shales and sandstones
accumulated round them and preserved them in the position in which they
grew.

I do not know that I can point out to you anything nowadays that exactly
resembles the state of things that must have gone on during the times
these coal measures were being formed; but there are a great many cases
strikingly analogous to them. I shall not attempt to describe them to
you, but may just mention the mangrove swamps that very often fringe the
coasts in the tropics, and the cypress swamps of the Mississippi, which
are so well described by Sir Charles Lyell in his recent works; also
the great Dismal Swamp of Virginia, which appears to me to furnish the
nearest analogue to the state of things that existed during coal measure
times.

Having explained the way in which coal measures have been formed, we
will now take a brief sketch of its uses and products. The year 1259 is
memorable in the annals of coal mining. Hitherto the mineral had not
been raised by authority, but in that year Henry III. granted a charter
to the freemen of Newcastle-on-Tyne for liberty to dig coal, and a
considerable export trade was established with London, and it speedily
became an article among the various manufacturers of the metropolis. But
its popularity was but short lived. An impression became general
that the smoke arising therefrom contaminated the atmosphere and was
injurious to public health. Years of experience have proved the fallacy
of the imputation; but in 1306 the outcry became so general that a
proclamation was issued by Edward I forbidding the use of the offending
fuel, and authorizing the destruction of all furnaces, etc., of those
persons who should persist in using it. Prejudice gradually gave way as
the value of the fossil fuel became better known, and from that time
downward its use has become more and more extended down to the enormous
extent of our present trade. The annual increase in the production of
coal in the British Isles since the year 1854 is over 2½ million tons.
In that year the coal produce was about 65 million tons, and it has
grown up to the year 1880 to the grand total of 135 million tons.

We will now deal with some of the uses that this valuable black diamond
is now being put to. It is, in the first place, the center of all our
enterprise and prosperity, and upon it depends our chief success as a
manufacturing nation for the future. When it is exhausted we shall have
to look forward to the condition of things which now obtains in those
regions where there is no coal--that is to say, instead of our being a
nation full of manufacturing and mercantile enterprise, a great nation
to which all the people of the earth resort, we shall be merely a people
who live for ourselves by the cultivation of the ground. The duration of
our coal fields has been ascertained within certain limits. Mr. Hall, an
accomplished geologist, tells us that in England at the present time we
have a stock of coal sufficient for our consumption for no less than
1,000 years. On the other hand, Professor Jevons, whose opinion is
worthy of the very greatest weight on such questions, calculates that
100 years is about the tenure of our coal fields, according to the
present rate of increase in the consumption. Whichever view we take,
sooner or later the end must ultimately come when the coal will be
exhausted; when the great mainspring of our commercial enterprise will
be gone, and we shall revert to that condition in which we were before
the coal fields were worked. In this point of view, therefore, coal has
an especial interest to us as engineers. If coal is important in this
direction, it is no less important in a purely scientific point of view,
apart from any mercantile end.

The chemist or physicist will tell you the wondrous story that the black
substance which you burn is simply so much light and heat and motion
borrowed from the sun and invested in the tissues of plants. He will
tell you that when you sit round your firesides the flame which enlivens
you, and the gas which enables you to read, and which civilizes you, is
nothing in the world but so much sunlight and so much sunheat bottled up
in the tissues of vegetables, and simply reproduced in your grates and
gas burners. Very few persons, I am afraid, realize this, which is one
of the many stories which science in its higher teachings shows us--one
of those fairy tales which are the result of the most careful scientific
investigation. Of the hundred and odd million tons of coal which we in
this country burn in the course of a year, about 20,000,000 tons are
thrown on our house fires; 30,000,000 tons find their way into our blast
furnaces, or are otherwise used in the smelting and manufacture of
metals; about 48,000,000 are burnt under steam boilers; 6,000,000 are
used in gas-making; while the remainder is consumed in potteries, glass
works, brick and lime kilns, chemical works, and other sundries which I
need not speak of.

To go into the chemistry of coal is quite sufficient to take up more
time than I have at my disposal this evening, therefore I will briefly
touch on a few of the main points. Coal gas is made, as you are all
aware, by heating coal or cannel, which is the special form of coal
most valued for the purpose, on account of the high quality of gas it
produces in cylindrical fireclay retorts.

The by-products obtained in the manufacture of coal gas, the tar and the
ammonia water, are nowadays scarcely less important than the coal gas
itself. The ammonia water furnishes large quantities of salts to be
used, among other applications, as food for plants. We thus restore
to-day to our vegetation the nitrogen which existed in plants of
primeval times. The tar, black and noisome though it be, is a marvelous
product, by the reason of scores of beautiful substances which are
concealed within it.

Coal tar when distilled yields three main products: naphtha, dead oil,
and pitch or asphalt. The naphtha on redistillation yields benzine, from
which are prepared some of our most beautiful dyes; the dead oil, as
the less volatile portion is termed, furnishes carbolic acid, used as a
disinfectant and antiseptic, together with anthracene and naphthaline;
all three substances the starting points of new series of coloring
matters.

This discovery of these coloring matters marks an era in the history
of chemical science; it exercised an extraordinary influence on the
development of organic chemistry. Theoretical and applied chemistry were
knit together in closer union than ever, and dye followed dye in quick
succession; after mauve came magenta, and in close attendance followed a
brilliant train of reds, yellows, oranges, greens, blues, and violets;
in fact, all the simple and beautiful colors of the rainbow.

But there is still another story of coal tar to be told. Among the
many curious substances that wonderful fluid contains is the beautiful
wax-like body called paraffine, the development of which chiefly owes
its origin to the genius and energy of Mr. James Young. As early as
1848, Mr. Young had worked a small petroleum spring in a coal mine in