place. In this way the camera and the spectroscope are combined and
this helps chemists to compare the _spectra_ of different burning
substances far better than they could do with the naked eye alone.

To photograph the spectrum of the Sun the eyepiece of the big telescope
is taken out and the end of the tube of the spectroscope with the slit
in it is fitted in its place. In making a photograph of the spectrum of
a star the slit is not needed, for the light of the star itself is but
a mere point.

In photographing the spectrum of the Sun and stars three wonderful
instruments are combined, namely, the _telescope_, the _spectroscope_
and the _camera_; perhaps I should have said four wonderful
instruments, for without the _brain_ of a genius using them the Sun and
stars never would have given up their secrets.

APPENDICES

APPENDIX A

According to the official _Handbook of the Boy Scouts_, if you are a
Scout and want to win a merit badge for starcraft, you must

    (1) _Have a general knowledge of the nature of the
        stars and planets._

      (a) By the nature of the stars and planets is meant
          their colors and what they are made of. Their
          sizes and their distances from the Earth in a
          general way may also be included.

      (b) It is easy to tell the color of both the stars
          and the planets by looking at them, or by looking
          them up in the foregoing chapters.

      (c) The spectroscope shows that the stars are made
          of metals and gases and other substances which
          we have on Earth. The planets are probably
          made of the same kinds of metals, gases and
          substances as those which form the Earth, but
          there is no way of proving this, for the planets
          shine by reflected light, and in this case the
          spectroscope is of little use.

      (d) The stars are known to be suns as large or larger
          than our Sun; while the planets are about as
          large as our Earth--some smaller and some larger.

      (e) All of the planets are within 2,800 millions
          of miles of the Earth, while the nearest star,
          except our Sun, is 25 trillions of miles from the
          Earth, or 8,000 times as far away.

    (2) _Have a general knowledge of the movements of the
        stars and planets._

      (a) While all the stars revolve in orbits and are
          moving through space at high speed, they are so
          far away from us that they seem to be fixed and
          for all practical purposes they may be considered
          to be fixed in their positions.

      (b) All the planets turn on their own axes and travel
          in orbits round the Sun.

    (3) _Point out and name 12 principal
        constellations._

      (a) Twelve easy constellations are: (1) The Big
          Dipper; (2) The Little Dipper; (3) Cassiopeia;
          (4) Pegasus; (5) Orion; (6) Auriga and (7)
          Taurus, all of which are shown in Chapters I
          and II; (8) Gemini; (9) Leo; (10) Virgo; (11)
          The Scorpion, and (12) Sagittarius, which are
          constellations of the zodiac, and are shown in
          Chapter XI.

    (4) _Find the_ =North= _by means of other
        stars than the Pole Star_ (_which is the North
        Star_) _in case that star is obscured by
        clouds._

      (a) This can be done by finding the constellation of
          Cassiopeia, see Chapter I; and also by Pegasus;
          Auriga and Orion, as explained in Chapter II.

    (5) _Have a general knowledge of the positions and
        movements of the Earth, Sun, Moon, and the Planets;
        and of tides, eclipses, meteors and comets._

      (a) By reading the chapters on the Sun, Planets,
          Earth and Moon and

      (b) Other things in the sky carefully, you will be
          able to pass the requirements named in No. 5.

    (6) _Plot on at least two nights per month for six
        months the positions of all naked eye planets
        visible between sundown and one hour thereafter.
        The plot of each planet shall contain at least
        three fixed stars with their names or designations;
        colors of planets and stars are to be recorded as
        observed._

       (a) How to plot the position of a planet is fully
          explained in the chapter on Planets, but you
          should also read the one on The Stars of the
          Zodiac, and have a good star map (App. O).

APPENDIX B.

=Figures.=--When explaining the positions and forms of things, it is
often necessary to use certain terms and figures, that is to say, lines
which are either real or imaginary, but which can be drawn on paper.
See Fig. 185.

(1) A _straight line_ is, of course, a line which runs uniformly in the
same direction, and which is regular and without curves. A straight
line is the shortest distance between two points. (2) When we say that
lines are _parallel_, we mean that they lie so that every part of each
is equally spaced from the other. (3) A line is _horizontal_ when it
is parallel with the level surface of the Earth under it. (4) A line
is _perpendicular_ to the surface of the Earth when it is _plumb_,
that is, in a line with the center of the Earth. (5) A _vertical line_
generally means a plumb line. (6) A _right angle_ is formed when a
vertical, or a perpendicular, line meets a horizontal line. (7) A
_circle_ is a curved line, all points of which are equally distant from
its center. _Circular_ means round like a circle. (8) By _diameter_
is meant a straight line drawn from one side, or half of a circle, to
the opposite side through its center. (9) The _radius_ of a circle is
a straight line drawn from the center of a circle, or a ball, to its
circumference. (10) A _ring_ is a disk or object having a circular hole
cut in its center. (11) An _arc of a circle_ is a part of a circle.
(12) A _quarter circle_ is, of course, the one-fourth part of a circle.
(13) A _tangent_ is a line which touches a curve but does not cut it.
(14) An _ellipse_ is an oval figure, drawn on a plane surface. (15) The
_equator_ is a circle which divides the Earth or other ball into equal
parts, and is 90 degrees from the north and south poles. (16) The
_ecliptic_ is a circle round the Sky in whose plane lies the orbit of
the Earth.

[Illustration: FIG. 185.--GEOMETRICAL FIGURES.]

APPENDIX C

THE GREEK ALPHABET

Many of the brighter stars have names, as Aldebaran, Capella, Sirius,
etc., but astronomers now indicate the stars of a constellation by
the letters of the Greek alphabet. The usual method is to call the
brightest star of a constellation α, that is, Alpha, the next brightest
β which is Beta, and so on, but sometimes the stars are lettered in
order of position in the sky.

The following is the Greek alphabet:

    α Alpha      ν Nu
    β Beta       ξ Xi (Zi)
    γ Gamma      ο Omicron
    δ Delta      π Pi
    ε Epsilon    ρ Rho
    ζ Zeta       σ Sigma
    η Eta        τ Tau
    θ Theta      υ Upsilon
    ι Iota       φ Phi
    κ Kappa      χ Chi
    λ Lambda     ψ Psi
    μ Mu         ω Omega

APPENDIX D

STAR TESTS FOR EYESIGHT

There are a number of stars which are considered to be good tests for
the seeing power of the eyes. The faint stars of the Pleiades are a
fine test of this kind; but usually these tests are double stars and
while one will be bright and easily seen its companion will be very
faint. The test is to see the faint one, and if you can see it you may
consider you have very good eyesight.

Eyesight tests are given on the following pages:

    Page
     11--Mizar and Alcor
     34--Spots on the Sun
     94--Grimaldi on the Moon
    119--Nebula in Orion
    150--Epsilon in Lyra
    150--Pleiades
    182--Alpha and Beta in Capricornus

APPENDIX E

MAGNITUDES OF STARS

There are not nearly as many stars in the sky as you might at first
suppose. The stars are divided into magnitudes, that is, according
to their brightness. Stars of the first magnitude are the brightest
stars; stars of the second magnitude are second brightest, and so on.
The total number of stars which can be seen with the naked eye on any
one night in the United States is probably not more than 3,000. The
following table gives the number of stars of the different magnitudes
up to and including the sixth:

    Magnitudes     Number of Stars
       1st                   20
       2nd          about    65
       3rd          about   200
       4th          about   500
       5th          about 1,400
       6th          about 5,000

APPENDIX F

FIRST MAGNITUDE STARS

The brightness of a star is known by its magnitude. A star of the first
magnitude is one of the 20 brightest stars, and is 2½ times as bright
as a star of the second magnitude; a star of the second magnitude is
2½ times as bright as a star of the third magnitude; and so on. A star
of the sixth magnitude can just be seen with the naked eye on a clear
night when there is no Moon.

Fifteen of the twenty first magnitude stars can be seen in our
latitude, and these are:

                                      & OF
        & OF STAR                CONSTELLATION

     1. Sirius, the Dog Star, in    Canis Major
     2. Capella                “    Auriga
     3. Arcturus               “    Bootes
     4. Vega                   “    Lyra
     5. Rigel (β)              “    Orion
     6. Procyon                “    Canis Minor
     7. Betelgeux (α)          “    Orion
     8. Altair                 “    Aquila
     9. Aldebaran              “    Taurus
    10. Spica                  “    Virgo
    11. Antares                “    Scorpius
    12. Pollux                 “    Gemini
    13. Regulus                “    Leo
    14. Deneb                  “    Cygnus
    15. Fomalhaut              “    Piscis Australis

APPENDIX G

CONSTELLATIONS HAVING FIRST MAGNITUDE STARS

The following important constellations are not described in the
foregoing chapters of this book. They can be found, though, without
trouble, since a star of the first magnitude is located in each.

_Canis Major, the Big Dog_, is a winter constellation, and can be
seen on your meridian at 9 o’clock P. M. in February. Look for it in
the southern sky and you will quickly find it because of the dazzling
brightness of _Sirius_, the Dog Star.

_Bootes_ (pronounced Bo-ō´-tes), the Bear Leader, is a summer
constellation, and can be seen on the meridian at 9 o’clock P. M. in
June. It is to the north of the ecliptic, or path of the Sun. It lies
between a crown of stars and Virgo. You can’t miss it, for midway is
_Arcturus_, a red star of the first magnitude.

_Lyra, the Lyre._--Is a summer constellation, and can be seen on the
meridian at 9 o’clock P. M. in August. Look for it almost overhead, and
you can’t mistake it, for three bright stars, of which _Vega_ is one,
form a triangle.

_Canis Minor._--The Little Dog: is a spring constellation, and can be
seen on the meridian at 9 o’clock P. M. in March. It lies to the south
of the constellation of Gemini, the Twins, and Cancer, the Crab. In it
you will see _Procyon_, the Little Dog Star.

_Aquila, the Eagle._--Is a summer constellation, and can be seen on the
meridian in August. Look for it south of Lyra, and far to the west of
Pegasus. The star that put Aquila on the map is _Altair_.

_Cygnus, the Swan._--Is also a summer constellation, and can be seen
on your meridian at 9 o’clock P. M. in September. You will find it
north of Pegasus and east of Lyra, and in it you will see the _Northern
Cross_ clearly traced out with seven stars, the brightest one being
_Deneb_, a first magnitude star.

Piscis Australis, the Southern Fish, is an inconspicuous constellation
far south of the Equator. Fomalhaut, its brightest star comes only 20
degrees above our horizon and must be looked for when it is near the
meridian--about 9 o’clock P. M. in October.

APPENDIX H

COLORED STARS

You can easily notice that the stars differ in color. The following
list gives the colors of a few of the brighter stars:

    WHITE STARS:  Sirius, Regulus, Vega.
    BLUE STARS:   Rigel and Spica.
    RED STARS:    Aldebaran, Antares, and Betelgeux.
    GREEN STARS:  B Librae.
    YELLOW STARS: The Sun, Arcturus, and Capella.

APPENDIX I

DOUBLE STARS

When two stars are very close together they form what is called a
_double star_, but double stars of which the two components are really
near together in space and revolve around each other usually cannot
be resolved, that is separated, into two stars without the aid of a
telescope.

The North Star; Rigel, Castor; Procyon and Sirius, are all famous
double stars.

APPENDIX J

VARIABLE STARS

A variable star is one whose brightness changes from time to time.
A great many variable stars are known, but very few of them can be
seen with the naked eye. There are different reasons given for a star
varying in brightness. Our Sun is a variable star, and we are told that
this is due to his spots. Another type of variation is perhaps produced
by pulsations--the star periodically expanding and contracting. Again a
double star formed of two bright stars which revolve round each other,
as many double stars do, may eclipse one another, and this would cause
a change in brightness. Here, then, are three good reasons for a star
being variable.

The following are a few of the _variables_ which can be seen with the
naked eye:

    _Betelgeux_, in Orion.
    _Alpha Cassiopeia_, that is, the brightest star in Cassiopeia.
    _Beta Lyra_, that is, the second brightest star in Lyra, and
    _Beta Pegasus_, that is, the second brightest star in Pegasus.
    _Mira_, in Cetus.
    _Algol_, in Perseus.

APPENDIX K

INVISIBLE OR DARK STARS

Stars are born, live and die, just like human beings. All the stars,
including the Sun, are either in the process of making, are at their
brightest brilliancy, are dying out, or are cold and dead or have not
yet become bright.

Procyon and Sirius is each attended by a comparatively dark companion.
Procyon and Sirius both move slowly back and forth a short distance in
the sky and this motion was attributed to the pull of satellites long
before these bodies were discovered with the telescope.

APPENDIX L

THE EQUATION OF TIME

                     TABLE OF THE EQUATION OF TIME

    --------+---------+---------+---------+---------+---------+--------
     Day of | January |February |  March  |  April  |   May   |  June
     Month  |         |         |         |         |         |
    --------+---------+---------+---------+---------+---------+--------
            |_m_  _s_ |_m_  _s_ |_m_  _s_ |_m_  _s_ |_m_  _s_ |_m_  _s_
       1    |S  3  31 |S 13  44 |S 12  37 |S  4   6 |F  2  56 |F  2  30
       6    |S  5  49 |S 14  15 |S 11  33 |S  2  37 |F  3  27 |F  1  41
      11    |S  7  59 |S 14  27 |S 10  19 |S  1  14 |F  3  45 |F  0  44
      16    |S  9  49 |S 14  19 |S  8  57 |F  0   4 |F  3  48 |S  0  18
      21    |S 11  24 |S 13  52 |S  7  28 |F  1  12 |F  3  38 |S  1  23
      26    |S 12  39 |S 13  10 |S  5  56 |F  2  10 |F  3  15 |S  2  27
      31    |S 13  35 |S 12  13 |S  4  24 |F  2  56 |F  2  39 |S  3  38
    --------+---------+---------+---------+---------+---------+--------

    --------+---------+---------+---------+---------+---------+---------
     Day of |  July   | August  |September| October |November |December
     Month  |         |         |         |         |         |
    --------+---------+---------+---------+---------+---------+---------
            |_m_  _s_ |_m_  _s_ |_m_  _s_ |_m_  _s_ |_m_  _s_ |_m_  _s_
       1    |S  3  28 |S  6  10 |S  0   6 |F 10   8 |F 16  18 |F 11   3
       6    |S  4  24 |S  5  46 |F  1  31 |F 11  41 |F 16  17 |F  9   3
      11    |S  5  11 |S  5   8 |F  3  13 |F 13   4 |F 15  56 |F  6  51
      16    |S  5  46 |S  4  15 |F  4  58 |F 14  16 |F 15  13 |F  4  30
      21    |S  6   9 |S  3   9 |F  6  45 |F 15  13 |F 14  10 |F  2   2
      26    |S  6  11 |S  1  51 |F  8  29 |F 15  54 |F 12  45 |S  0  28
      31    |S  6  12 |S  0  24 |F 10   8 |F 16  16 |F 11   3 |S  2  55
    --------+---------+---------+---------+---------+---------+---------

As we have seen in Chapter X every day of the year is exactly 24 hours
long by our clock time. The time by the Sun is usually either ahead or
behind local clock time. The difference between clock time and Sun time
is called the _equation of time_, and a table to show how many minutes
and seconds the Sun is fast or slow, according to clock time, is given
above, taken from “The New Astronomy,” by Professor Todd, who has
kindly permitted me to use it here. In the table =S= means that the Sun
is slow, that is, that the Sun does not cross the meridian until after
the clock shows noon, and =F= means that the Sun is fast, that is, that
the Sun has crossed the meridian before the clock shows noon. =m= means
minutes, and =s= means seconds above the figures.

The table gives the average values of the equation of time, which may
differ by a few seconds from the values for any particular year.

APPENDIX M

THE KULLMER STAR FINDER

The star finder shown in the picture was invented by Dr. C. J.
Kullmer, of Syracuse, N. Y., and has been highly praised by many great
astronomers.

[Illustration: FIG. 186.—KULLMER STAR FINDER.]

You should own one if possible, for you do not need to know anything
about the stars to operate it. It is mounted on the principle of a big
telescope, but it is a naked eye instrument, an arrow taking the place
of the telescope.

The finder is placed on a table, or other level surface, with the
dial facing north. Then the pointer and dial are set for the day
and hour when you want to find the position in the sky of a certain
constellation. The indicator is turned to the name of the constellation
on the dial, and this also tells the direction to set the arrow.

This is all there is to it and the arrow points right at the group of
stars you want, whether they are above the horizon or not.

The finder can be used for many purposes, and it is a wonderful aid in
making out in the sky the path of the stars, Sun, Moon and planets,
and when they rise and set. In fact, it is a complete observatory on a
small scale. Its cost is only $5.00.

APPENDIX N

THE ELLIS SEASONAL TWILIGHT CHART

A useful chart, designed by Miss E. Rebecca Ellis, of Wellesley
College, Wellesley, Mass. It makes clear the changes in the lengths of
the day, the phenomena of the seasons, etc. Its price is $1.00.

APPENDIX O

THE CAMP FIRE SKY MAP

This map, prepared by Prof. R. S. Dugan of Princeton University, shows
the constellations as far south as the Southern Cross and is adjustable
for the time of night, date, and for the latitude. Full instructions
are given for its use. It is used in many schools and colleges. It is
sold by the Camp Fire Stores Co., price 19 cents.

DEFINITIONS OF SOME WORDS AND TERMS USED IN THIS BOOK

    =Action.= The way in which a thing works.

    =Affect.= To act upon; to change; to be moved or
       influenced by.

    =Almanac.= A pamphlet or book containing tables
       showing the days of the year; also the time the Sun
       and Moon rise and set; the conjunctions, eclipses
       and other information concerning the things in the
       sky. The word almanac is supposed to be derived
       from the Arabic article _al_ and the verb
       _manac_, which means to count.

    =Angular measurements.= See Appendix B.

    =Aphelion.= The point where a planet or a comet is
       farthest away from the sun.

    =Apparent.= To seem real. The daily motion of the
       Sun round the Earth is only apparent, for we know it
       is the Earth which turns round on its axis instead.

    =Arc.= See Appendix B.

    =Arc of circle.= See Appendix B.

    =Aspect.= (1) Any curious appearance of an object,
       especially if the object changes in appearance.
       (2)The figure formed by a planet with the stars of
       the constellation which it is in.

    =Astrologer.= One who forecasts the life of a
       person on the supposition that the stars control it.

    =Astronomer.= One who is skilled in seeing the
       stars and who knows them.

    =Atom.= A very small particle of matter. See
       Molecule; Matter.

    =Attract.= To pull toward. The attraction of
       the Sun and the Earth for each other is due to
       gravitation.

    =Attraction.= A force which pulls one body to
       another.

    =Attraction of Gravitation.= A force which pulls
       all bodies to each other.

    =Auditory nerve.= A nerve that carries the
       impressions of sound which reach the ear to the
       brain.

    =Aurora borealis.= The Northern Lights. A glowing
       light effect which takes place in the Arctic Circle.
       It can often be seen from our Northern States and
       sometimes from the Southern States. The same kind of
       lights appear in the Antarctic Circle. These Southern
       Lights are called Aurora Australis.

    =Axes.= Plural of axis.

    =Axis.= An imaginary line on which a body turns.

    =Axis of rotation.= An imaginary line round which
       anything turns or spins.

    =Axle.= A wood or metal rod on which one or more
       wheels turn, or it may turn with the wheel or wheels.

    =Badge of merit.= A badge awarded by the
       organization of Boy Scouts to members who can show a
       certain amount of skill in doing certain things. See
       Appendix A.

    =Band.= (1) A flat strip of any material, or (2)
       such a strip whose ends are joined together.

    =Beam.= Rays of light which are parallel. See Ray.

    =Bearing.= (1) A piece of metal, or a bit of agate
       or other jewel, on which a pivot, spindle or shaft
       turns. (2) A direction as found by the Sun or stars,
       or by the compass, sextant or other means.

    =Body.= Any separate and distinct amount of matter
       when held together. The Sun and Moon are heavenly
       bodies.

    =Degree.= (1) The 360th part of a circle. (2)
       Indicated by this sign °.

    =Device.= (1) An apparatus or instrument or any
       part thereof. Any arrangement for producing a
       given result.

    =Diagram.= A sort of shorthand picture of an
       apparatus or part of an apparatus. It is used
       to show in the simplest and clearest manner the
       construction of an apparatus.

    =Diameter.= See Appendix B.

    =Direct line.= A straight line.

    =Disk.= (1) A circular plane or flat surface.
       Since the Sun, Moon and planets seem to be flat
       their surfaces are called disks. (2) Flat and
       circular like a coin.

    =Dog days.= So called from the fact that Sirius,
       the Dog Star, rises at the same time as the Sun.

    =Ecliptic.= See Appendix B.

    =Elastic.= (1) A body that will stretch and return
       to its original size. (2) A thin piece of rubber.

    =Ellipse.= See Appendix B.

    =Equator.= See Appendix B.

    =Equatorial.= Having to do with or affected by the
       equator.

    =Equatorial telescope.= A telescope so mounted
       that its principal axis is parallel with the axis
       of the earth and moved by clockwork so that it will
       follow a star.

    =Evening Star.= A planet which can be seen in the
       west just after the sun sets.

    =Fixed.= (1) Fastened securely. (2) The stars are
       called fixed because they never seem to change their
       positions.

    =Forecast.= A prediction of some future event.
       A forecast may be founded on fancy or on fact. A
       horoscope of a person is a forecast based on the
       fancy of an astrologer. A weather forecast is
       founded on the action of a barometer, and even then
       the forecast is uncertain enough. Forecasts of the
       time of eclipses, the return of comets and the like
       are founded on cold scientific facts and hence come
       true at exactly the calculated time.

    =Frequency.= How often an event occurs.

    =Gas.= That form of matter which is like air.
       Some gases remain in the gaseous state at ordinary
       temperatures. Gases have a tendency to expand
       without limit. See Vapor.

    =Generate.= To produce. To set up; as a battery
       generates a current; the Sun generates power.

    =Gravitation.= The force which attracts all bodies
       near the Earth to it and all bodies to each other.

    =Heavens.= The sky. The space as far as the eye
       can see about the Earth. The space in which the
       stars and their planetary systems move.

    =Horizontal.= See Fig. 185.

    =Horoscope.= A forecast of the future of a person
       made by an astrologer who pretends to read the future
       from the aspect or position of the planets and stars.

    =Hyperbola.= See Fig. 129.

    =Hypothesis.= See Idea.

    =Idea.= A notion of a plan or scheme which may be
       more or less vague. =Supposition.= A clearer
       conception of a plan or scheme which is based on
       such facts as may be thought of. =Hypothesis.=
       A plan or scheme assumed to be true and carefully
       reasoned out from all the facts obtainable.
       =Theory.= A plan or scheme which has been
       proved true by experiment, examination or comparison.

    =Illusion.= An image which deceives the eye. The
       other senses can also be deceived by illusions.

    =Impact.= Coming together of two objects.

    =Impress.= To form on, or to affect, as light
       waves impress a dry plate.

    =Indicate.= To show. To point out.

    =Indicator.= That which points out or shows
       something.

    =Limb.= The edge of the Sun, Moon or Planets.

    =Lore.= Learning on any subject.

    =Lunar.= Of, or having to do with the Moon.

    =Magnetic lines of force.= The direction of the
       force of magnetism acting in and around a magnet.

    =Magnetic storm.= The Earth is a great magnet and
       sometimes when sun spots of unusual size or numbers
       appear, the magnetic lines of force of the Earth are
       violently affected. This is called a magnetic storm.

    =Mass.= (1) Amount of matter. (2) A lot of
       molecules or particles of matter brought and held
       together.

    =Matter.= The substance of which a thing is
       formed. A molecule of matter is made up of atoms,
       and a mass is a lot of molecules held together by
       some attractive force.

    =Mercury.= (1) The name of the planet nearest the
       Sun. (2) A silver white liquid metal.

    =Molecule.= The smallest part of matter that can
       exist separately without the substance it forms
       being destroyed.

    =Morning Star.= A planet which can be seen in the
       east just before the Sun rises.

    =Morse code.= A telegraph code of dots and dashes
       invented by Samuel F. B. Morse. The Morse Code is
       used for telegraph and heliograph signaling.

    =Motion.= Anything that changes position. There
       are two kinds of motion (a) simple motion and
       (b) compound motion. _Simple motion_ can be
       either _translated_ or _rotary_, while
       _compound motion_ is both _translated_
       and _rotary_, so that while a body is being
       translated, or moved through space, it is also
       rotating on its axis. The Sun and planets, then,
       have compound motions.

    =Nature.= Everything contained in space that has
       not been shaped by human hands.

    =Nautical almanac.= The American Nautical
       Almanac is a book of the stars published by the
       Bureau of Navigation of the United States. It is
       published three years in advance and is sold by the
       Superintendent of Documents, Washington, D. C., at
       30 cents per copy. This is designed chiefly for
       the use of navigators of ships. It gives the exact
       positions of the Sun, Moon and planets and much
       other astronomical information. It is based upon
       the calculations made by the United States Naval
       Observatory; these are printed in the Nautical
       Almanac, and on this all other almanacs are based.

    =Northern lights.= See Aurora Borealis.

    =Obscured.= Hidden from sight.

    =Official Handbook of the Boy Scouts.= A book
       published by the organization of Boy Scouts and
       which contains the rules and regulations of that
       organization and the requirements they must meet in
       order to win merit badges.

    =Offset.= To equal; to balance.

    =Opposition.= See Appendix.

    =Optic Nerve.= The nerve that carries the
       impression of light received by the eye to the brain.

    =Orbit.= The path followed by a body. Atoms have
       orbits as well as the stars. The paths followed by
       planets and comets round the Sun.

    =Parabola.= See Fig. 129.

    =Parallel.= See Appendix B.

    =Particle.= A bit of matter. A particle may be a
       bit of matter which can be seen or it may mean an
       amount so small that it cannot be seen.

    =Pencil.= A group of rays from the same source of
       light. See Beam. See Ray.

    =Pendulum.= A body suspended from a fixed point
       and free to swing.

    =Perihelion.= The point where a planet or a comet
       is nearest the Sun. As the orbit of a planet is an
       ellipse and the Sun is in one of the foci—that is
       near one end—a planet comes nearest to the Sun when
       at this end of the ellipse; and when the planet is
       at the other end of its orbit, it is farthest away.
       See Aphelion.

    =Period.= A certain interval of time which is
       marked by a repeated occurrence. The period of the
       Earth round its axis is about 24 hours. Its period
       around the Sun is 365¼ days.

    =Periodic.= Recurring regularly; as a periodic
       comet.

    =Perpendicular.= See Appendix B.

    =Phase.= One of the peculiar aspects of a heavenly
       body; as the phases of the Moon, or the phases of Venus.

    =Pivot.= A pin, spindle or shaft on which a wheel,
       lever or device rotates or is rotated.

    =Plane.= A level surface, as a table top.

    =Point.= A sharp end. A starting place.

    =Pores.= Minute spaces which separate the
       molecules of a substance.

    =Position.= The place of a thing when compared to
       the places of other things.

    =Precede.= To go ahead of. That which is before.

    =Precession.= The act of going ahead or preceding.
       When a revolving body such as a spinning top or
       the Earth is acted upon by forces which tend to
       change the direction of its axis. This change in
       the direction of its axis is called _precessional
       motion_. The pole of the equator of the Earth
       makes a complete turn round the pole of the ecliptic
       in a little over 25,000 years and this change in the
       direction of the axis of the Earth causes the points
       of the _equinox_, that is the places where the
       _ecliptic_ and the _equator_ cross each
       other to move slowly from west to east and this is
       termed the precession of the equinoxes.

    =Prediction.= To foretell; to forecast.
       Predictions may be based on fancy or founded on fact.

    =Principal.= The chief one; the most important.

    =Principle.= The cause of a result. That on which
       a thing is based.

    =Process.= (1) The way of working. (2) The course
       of procedure.

    =Produce.= In astronomy the word _produce_
       means the lengthening of a line. It is a
       mathematical term.

    =Protractor.= See Fig. 98.

    =Quarter circle.= See Appendix B.

    =Ray.= (1) A single line of light or heat. (2) The
       path of light and heat.

    =Relative position.= The position of a thing when
       compared with the position of something else. See
       Position.

    =Revolution.= The turning of a thing completely
       round on its axis.

    =Revolve.= (1) To turn completely round a circle.
       (2) To turn on an axis, as a top, or the Earth.

    =Rigid.= Firm, that which cannot be easily moved
       out of its place.

    =Ring.= See Appendix B.

    =Rise.= To come into sight above the horizon, as
       the Moon rises.

    =Rotate.= To turn completely round on an axis like
       a top or the Earth.

    =Rotary.= Turning completely round on an axis,
       like a top or the Earth.

    =Roughly.= Not exactly; nearly enough for
       practical purposes.

    =Schedule.= (1) A tabulated statement giving items
       concerning a subject. (2) A timetable of any kind.

    =Seeing.= To look at. The word _seeing_
       in starcraft means to observe the stars. _Good
       seeing_ is to observe the stars when the
       atmosphere is perfectly clear.

    =Seems.= Something which apparently is true and
       yet is not necessarily true.

    =Sensation.= The action of one of the senses when
       excited by some change in matter. Light falling on
       the retina of the eye produces the sensation of
       light and color in the brain.

    =Set.= To sink from sight below the horizon; as
       the Sun sets.

    =Sight.= The power to see. See Sighting.

    =Sighting.= To get the eye and two other objects,
       such as a telescope and a star, in a line, as to
       sight Jupiter with a telescope.

    =Sign.= A mark, figure or letter which astronomers
       have agreed to use to represent certain stars,
       aspects of stars, parts of the zodiac, etc.

    =Solar.= That which is of, or has to do with the
       Sun.

    =Spring stars.= The stars which can be seen best
       during the spring months.

    =Star chart.= A map of the positions of the stars.

    =Starcraft.= Useful knowledge of the stars. Skill
       shown in making the stars serve useful purposes.

    =Star finder.= A device of any kind which will
       enable an unskilled person to find the planets or
       constellations.

    =Star-lore.= Learning concerning the mythology of
       the stars.

    =Summer stars.= The stars which can best be seen
       during the summer months.

    =Supposition.= See Idea.

    =Tangent.= See Appendix B.

    =Tangent line.= See Appendix B.

    =Telegraph code.= The alphabet of dots and dashes.

    =Test.= To try out. To examine, compare or make an
       experiment which will give a needed proof.

    =Theory.= See Idea.

    =Thumb tack.= A short, thin, sharp-pointed tack
       with a large flat head which permits it to be easily
       pushed into a board with the thumb. It is used by
       draftsmen for fastening paper to drawing boards.

    =Tilting.= Leaning from a vertical or plumb
       line. The axis of the Earth is tilted from the
       perpendicular 23½ degrees; this throws its equator
       out of plane with that of the sun, and the circle
       through the Earth that is in plane with the Sun is
       called the ecliptic.

    =Transparent.= Said of any substance through which
       light can pass easily. Anything that may be seen
       through.

    =Twinkle.= To blink. To flash with varying
       brightness. The twinkling of stars is caused by the
       atmosphere.

    =Uniform.= Being the same all through or all along.

    =Vapor.= A gas produced from a liquid or a solid
       and which returns to its original form at ordinary
       temperatures. See Gas.

    =Vertical.= See Appendix B.

    =Vibration.= A to-and-fro movement, as the
       vibration of a particle of matter. A constant
       to-and-fro movement over the same line.

    =Visible.= That which the eye can see.

    =Wane.= To gradually grow smaller. Said of the
       Moon.

    =Wax.= To gradually grow larger. Said of the Moon.

    =Winter Stars.= The stars which can best be seen
       during the winter months.

    =Wireless Messages.= Messages which are sent and
       received by wireless telegraph stations.

    =Wireless system.= An apparatus for sending and
       receiving messages by wireless telegraph.

    =Your meridian.= The line running due north and
       south in the sky directly over your head. A meridian
       of this kind is called a celestial meridian.

    =Zodiacal lights.= A faint glowing light which
       may be seen above the western horizon just after
       twilight during the clear evenings of winter and
       spring. It can also be seen just before daybreak
       during the clear mornings of summer and autumn.

INDEX

    Air, thickness of, around Earth, 125.
    Air waves, 125.
    Alcor, in the Big Dipper, 11.
      and Mizar through a glass, 150.
    Aldebaran in Taurus, 26, 28.
    Almanac, 171.
      how to read, 182.
      Old Farmers’, 184.
      signs in, 183.
      use of, for finding planets, 61.
    Alpha Centauri nearest star, 118.
    Alphabet, Greek, 197.
      Morse, 39.
    Andromeda, great nebula in, 119.
    Annular eclipse of the Sun, 112.
    Antares in Scorpio, 180.
    Apennines on the Moon, 146.
    Apparent noon, 154.
    Apparent solar day, 154.
    Apparent time, 152.
    Aquarius, the Water Bearer, constellation of, 63.
      the Water Man, 173.
    Aquila, the Eagle, 201.
    Arab test for eyesight, 11.
    Arc defined, 194.
    Arctic day and Sun, 87.
    Arcturus in Boötes, 28.
    Aries, the Ram, 63, 175.
    Aristarchus on the Moon, 146.
    Ass’s Colts in Cancer, 176.
    Asteroids, 47, 54.
    Astrologer’s horoscopes, 180.
    Atoms, vibration of, 123.
    Auditory nerve, 125.
    Autumn, 74.
    Autumnal equinox, 178.
    Auriga, Capella in, 24.
    Auriga, the Charioteer, 23.
      constellation of, 23.
      of the Greeks, 24.
      the Shepherd, 24.

    Barometer, a simple, 35.
    Barometric pressure, 35.
    Belt of Orion, 21.
    Beta Pegasi, 18.
    Betelgeux in Orion, 28.
    Big Dipper, the, 2, 4.
      Alcor in the, 11.
      how to tell time by the, 12.
      Mizar in the, 11.
      pointer stars of, 10.
      position of, in autumn, 3.
        in summer, 11.
        in spring, 10.
        in winter, 9.
      through a telescope, 149.
    Boötes, the Bear Leader, 201.
    Boxing the compass, 78.
    Boy Scout, merit badge for, 193.
    Boy Scouts’ Handbook, 193.
    Brain of a genius, 192.
    Bull of Light, the, 26.
    Burning lens, 37.

    Camera, how it is made, 185.
    Cancer, the Crab, 176.
    Candle flame, 30.
    Canis Major, constellation of, 28, 201.
    Canis Minor, the Little Dog, 201.
    Capella, how to find the North with, 24.
    Cardinal points of a compass, 78.
    Cassiopeia of the Arabians, 16.
      constellation of, 14.
    Castor and Pollux in Gemini, 176.
    Cave man, how he marked time, 152.
    Central time, 160.
    Centrifugal force, 58, 90.
    Chromosphere, the Sun’s, 32.
    Chronograph, how made and used, 162.
    Chronometer, use of, to find longitude, 85.
    Circle defined, 194.
    Colored stars, 202.
    Colored sun glasses, 30.
    Colors, how they are made, 123, 129.
    Combustion, what it is, 123.
    Comet, breaking up of, 116.
      coma of a, 113.
      Halley’s, 115.
      how to find a, 112.
      nucleus of a, 113.
      tail of a, 113, 116.
    Comets, laws of, 114.
      number of, 116.
      paths of, 113.
      speed of, 115.
    Compass, boxing the, 78.
      cardinal points of a, 78.
      dial, mariner’s, 78.
      how to make a simple, 77.
      mariner’s, 78.
      pocket, 78.
    Concave lens, 134.
    Constellations: Aquarius, the Water Bearer, 63.
      Aquila, 201.
      Aries, the Ram, 63, 173, 175.
      Auriga, 23.
      Big Dipper, 6.
      Boötes, 201.
      Cancer, the Crab, 176.
      Canis Major, 28, 201.
      Cassiopeia, 14.
      Cygnus, 201.
      Flying Horse, 19.
      Gemini, the Twins, 63, 176.
      Great Bear, 6.
      Great Square of Pegasus, 17.
      having first magnitude stars, 201.
      Libra, the Balance, 178.
      Little Bear, 16.
      Little Dipper, 15.
      Leo, the Lion, 177.
      Lyre, 201.
      Mighty Orion, 20.
      Northern Cross, 202.
      Pisces, the Fishes, 63, 174.
      Pleiades, 26.
      Plough, 6.
      Sagittarius, the Archer, 180
      Scorpio, the Scorpion, 180.
      Taurus, the Bull, 24, 175.
      Ursa Major, 6.
      Ursa Minor, 17.
      Virgo, the Virgin, 177.
      what they mean, 14.
      Zodiac, 168.
    Convex lens, 133.
    Copernicus on the Moon, 148.
    Corona of the Sun, 33.
    Crescent Moon, 93.
    Cycle of the Seasons, 75.
    Cygnus, the Swan, 201.

    Dark stars, 206.
    Day, solar, 154.
      when it begins and ends, 152.
    Definitions of words used in starcraft, 213.
    Degrees, dividing a circle into, 156.
      Earth divided into, 81.
      protractor for measuring, 79.
    Denebola in Leo, the Lion, 177.
    Dial of mariner’s compass, 79.
    Diameter defined, 194.
    Difference between true North Pole and magnetic North Pole, 88.
    Dipping needle, how to make a, 79.
    Dog Star, 8.
    Double stars, 204.

    Earth, 47, 54.
      cross section of, 67.
      divided into degrees, 81.
      divided into standard meridians, 158.
      from the Moon, view of, 104.
      a great magnet, 77.
      in the making, 66.
      Moon eclipsed by, 107.
      and Moon joined together, 89.
      orbit of, an ellipse, 70.
      precession of the, 173.
      proof it is round, 67.
      shadow of, 109.
      thickness of air around, 125.
      tilts on its axis, 69.
      travels round the Sun, 70.
      turning of, makes day and night, 69.
      turning in orbit makes the seasons, 72.
      turns on its axis, proof that, 68.
      umbra of, 135.
      when cooled off, 66.
    Earth-shine, 93.
    Eastern time, 158.
    Eclipse, annular of the Sun, 112.
    Eclipse, defined, 113, 194, 195.
      of the Moon, 107.
      partial, of the Sun, 112.
      seeing an, 107.
      of the Sun by Moon, 110.
        for next 30 years, 112.
      total, of the Sun, 112.
    Ecliptic, the, 46, 69, 72, 170.
    Ellipse, 113.
    Ellis seasonal twilight chart, 201.
    Epsilon in Lyra through a glass, 150.
    Equation of time, 155, 207.
    Equator, crossing the ecliptic, 72.
      defined, 194.
    Equinox, autumnal, 178.
      vernal, 178.
    Ether, what it is, 123, 125, 127.
    Evening star, Venus, 50.
    Experiment, Foucault’s pendulum, 68.
      in centrifugal force, 90.
      making star trails, 68.
      showing, eclipse of Sun, 110.
        how Moon cracked, 145.
        Moon eclipsed by Earth, 107.
        Moon’s crescent, 95.
        Moon’s day and year, 94.
        Moon’s phases, 98.
        reflection of light, 131.
        refraction of light, 132.
      with a bell, 125.
      with candle to show the seasons, 73.
      with cardboard zodiac, 170.
      with spinning top, 72.
      with water waves, 124.
    Eye, a camera, 127.
      how it sees, 127.
      human, 8.
      light and, 129.
    Eyesight, star tests for, 197.

    Finding, the North Star, 2.
      the North with Pegasus, 19.
    Fireballs, 116.
    First magnitude stars, 200.
    Fixed stars, 7.
    Flying Horse, constellation of, 19.
    Focal length of a lens, 134.
    Focus of lens, 133.
    Forecasting the weather by barometer, 35.
    Forecasting weather by signs, 36.
    Foucault’s pendulum experiment, 68.
    Fraunhofer’s lines, 190.
    Frequency of vibrating atoms, 123.
    Friction, 60.

    Gemini, the Twins, constellation of, 63, 176.
    Geometrical figures, 195.
    Gibbous Moon, 93.
    Girl in the Moon, 147.
    Gravitation defined, 59.
    Great Bear, 5.
    Great Square of Pegasus, constellation of, 17.
    Greek alphabet, 197.
    Greenwich time, 86.
    Grimaldi on the Moon, 94, 147.
    Guardian stars of the Little Dipper, 16.

    Handbook of Boy Scouts, 193.
    Harvest and Hunter’s Moon, 98.
    Heat, how it travels, 123.
    Heat, what it is, 122, 129.
    Heliograph, how to make and use a, 40, 41.
    Horizon, a good, 153.
    Horizon glass, 84.
    Horizontal line defined, 194.
    Horoscopes, astrologer’s, 180.
    Horse and Rider, 11.
    Hours, dividing a circle into, 157.
    How a camera is made, 185.
    How the cave man marked time, 152.
    How the eye sees, 127.
    How to find, Aries, the Ram, 174.
      a comet, 113.
      constellations of the Zodiac, 169.
      focus of a lens, 133.
      longitude 86.
      the North Star, 83.
        with dipping needle and protractor, 82.
        with sticks and pail of water, 83.
      power of a telescope, 143.
    How to get Sun time, 153.
    How to know, the stars, 14.
      you are at the North Pole, 87.
    How to look at the Sun, 148.
    How to make, a cheap telescope, 140.
      pinhole telescope, 138.
      simple compass, 77.
      simple dipping needle, 79.
      star finder, 1.
      star trails, 187.
    How the Moon makes the tides, 99.
    How a photograph is made, 185.
    How a prism bends light, 133.
    How to read the almanac, 182.
    How a spectroscope is made, 191.
    How the stars shine, 121.
    How the stars were made, 119.
    How a telescope works, 139.
    How to tell, time by the Big Dipper, 12.
      a true meteorite, 117.
    How time is sent, by telegraph, 163.
      by wireless, 165.
    How to use a prism, 188.
    How we see light, 126.
    Hyades in Taurus, 175.
    Hyperbola, 113.

    Imaginary Sun time, 155.
    Index mirror, 84.
    Invisible stars, 206.

    Jupiter, 47, 61.
      nine moons of, 52.
      seeing, 51.
      through a telescope, 149.

    Kullmer star finder, 209.

    Latitude, how to find, by protractor and dipping needle, 82.
      with sextant, 84.
      with sticks and pail of water, 83.
    Lens, concave, 134.
      convex, 133.
      how to find focus of a, 133.
    Leo, the Lion, 177.
    Libra, the Balance, 178.
    Light, defined, 122.
      how made, 122.
      how it passes through glass, 130.
      how it travels, 123.
      how we see it, 126, 129.
      reflection of, 131, 132.
      refraction of, 132.
      speed of, 188.
      what makes the colors in, 123.
      wave-lengths of, 123, 130.
    Little Bear, constellation of, 16.
    Little Dipper, constellation of, 15.
    Local time, 86, 155.
    Longitude, how to find it, 86.
      meridians of, 86.
      use of sextant to find, 84.
    Lyra, the Lyre, 201.

    Magellan’s voyage, 67.
    Magnet, Earth a great, 77.
    Magnet, steel bar, 76.
    Magnetic lines of force, 76.
    Magnetic North Pole and true North Pole, 76, 88.
    Magnetic storms, 34.
    Magnitude of stars, 199.
    Man in the Moon, 93.
    Mariner’s compass, 78.
    Mars, 47, 49.
      is it peopled? 49.
      through a telescope, 149.
    Mean length, defined, 154.
    Mean solar time, 154.
    Mean time, 152.
    Mercury, 47, 48, 61.
      phases of, 48.
      through a telescope, 148.
    Meridian defined, 18.
      prime, 156.
      your, 61.
      zero, 156.
    Meridians, fixed, 157.
      of longitude, 85.
      standard, 86, 156.
    Meteorites, kinds of, 117.
      tests for, 117.
    Meteors, and meteorites, 116.
      orbits of, 116.
    Merit badge for starcraft, 193.
    Milk dipper in the Milky Way, 181.
    Milky Way, stars of the, 117, 118.
      through a glass, 150.
    Mizar in the Big Dipper, 11, 150.
    Moon, 89.
      Apennines on the, 146.
      aspects of the, 94.
      Copernicus on the, 148.
      crescent, 93.
      day and year of the, 94.
      and Earth joined together, 89.
      eclipse of the, 107.
      eclipse of Sun by the, 110.
      gibbous, 93.
      Grimaldi on the, 94, 147.
      Harvest and Hunter’s, 99.
      how it cracked, 144.
      if you were on it, 101.
      imitating volcanoes on the, 91.
      Man in the, 93.
      motions of the, 94.
      old, in the new Moon’s arms, 93.
      other things about the, 106.
      phases of the, how made, 94, 95, 96.
      photographing the, 188.
      seas on the, 144.
      seeing the, with the naked eye, 92.
      telling time by the, 105.
      through a telescope, 144.
      time marked by the, 151.
      a trip to the, 101.
      Tycho on the, 144.
      volcanoes on the, 91.
      weather, and the, 105.
      where it came from, 90.
    Moon girl, 146.
    Morning star, Venus, 50.
    Morse Code, 39.
    Motions of the Moon, 94.
    Mountain time, 160.

    Naked eye aids, 139.
    Naked eye view of the Moon, 93.
    Nebula, 114, 118.
      of Orion, great, 119.
    Nebular hypothesis, 119.
    Nebulæ, different forms of, 119.
    Neptune, the outpost planet, 47, 53.
      seeing, 53.
      through a telescope, 149.
    North, to find, by a watch, 45.
      with Capella, 24.
      with Orion, 23.
      with Pegasus, 19.
    North magnetic pole, 76.
    North Pole, 8.
      explorers at the, 87.
      how to know you are at, 87.
      shadows at, 88.
      true, and magnetic North Pole, 76, 88.
    North Star, 1, 2, 4.
      how to find, 1, 2.
      how to find latitude of, 83.
      sighting the, 2.
      through a glass, 150.
    Northern Cross, 202.
    Northern Lights, 34.

    Old Farmers’ Almanac, 184.
    Old Moon in the new Moon’s arms, 93.
    Opera glasses, 140.
    Optic nerve, 126.
    Orion, of the Arabians, 22.
      belt of stars of, 21.
      constellation of, 20.
      finding the North with, 23.
      the Great Hunter, 20.
      Great Nebula of, 119.
      sword of stars of, 22.

    Pacific time, 160.
    Parabola, 113.
    Partial eclipse of the Sun, 112.
    Pegasus, the Flying Horse, 19.
    Pendulum illustrating Sun’s attraction, 59.
    Penumbra, 135.
    Perpendicular line defined, 194.
    Phases, of Mercury, 48.
      of Venus, 50.
    Photograph, how made, 185.
    Photographing the Moon, 188
      the stars, 185.
    Photographing the Sun, 187.
    Photosphere of the Sun, 32.
    Pinhole sunshade, 30.
    Pinhole telescope, 30, 138.
    Pisces, the Fishes, constellation of, 63, 174.
    Plane, defined, 55.
    Planet, how to plot position of a, 61.
    Planetesimal hypothesis, 119, 120.
    Planets, eggshell experiment to show motions of, 57.
      first aid to remembering, 57.
      how held in space, 57.
      how to know the, 47.
      names and sizes of, 47.
      path of, 170.
      plane of, 55.
      round the Sun, position of, 54.
      the Sun’s kiddies, 46.
      through a telescope, 148.
      use of almanac for finding, 61.
      why they spin, 60.
    Pleiades, in Taurus, 26.
      through a glass, 150.
    Plotting the position of a planet, 61.
    Plough, the, 5.
    Pointer stars of the Big Dipper, 10.
    Polar nights, 71.
    Polaris, the Pole Star, 4.
    Pole Star, the, 4, 8.
    Precession of the Earth, 173.
    Prime meridian, 156.
    Prism, 132.
      forming a spectrum, 134.
      how to use, 188.
    Produce, defined, 8.
    Prominences of the Sun, 31.
    Protractor, showing degrees, 81.
      showing degrees latitude, 82.

    Radius defined, 194.
    Railroad time, 156.
    Reflection of light, 131.
    Regulus in Leo, the Lion, 177.
    Rigel in Orion, 28.
    Right angle defined, 194.
    Ring defined, 194.

    Sagittarius, the Archer, 180.
    Saturn, 47.
      seeing, 52.
      through a telescope, 149.
    Scorpius, the Scorpion, 180.
    Seasonal twilight chart, Ellis, 201.
    Seasons: autumn, 74.
      spring, 74.
      summer, 75.
      winter, 74.
      cycle of the, 75.
      Earth turning round Sun makes the, 72.
      experiment to show the, 73.
    Seeing, an eclipse, 107.
      the Moon with naked eye, 92.
      the stars, 121.
    Sextant, how to use it, 84.
    Shadow of, the Earth, 109.
      the Penumbra, 135.
      the Umbra, 135.
    Shadows, 135.
      at the North Pole, 88.
    Shooting the Sun, 84.
    Shooting stars, 116.
    Sighting the North Star, 2.
    Signalling with the Sun’s rays, 38.
    Signs, in the almanac, 183.
      of the Zodiac, 168.
    Sirius, the Dog Star, 8, 118.
    Sky, things in the, 107.
    Smoked Sun glasses, 30.
    Solar day, 154.
      apparent, 154.
    Solar noon, 153.
    Solar spectrum, 189.
    Solar system, in perspective, 56.
      top view of, 55.
    Solar time, 152.
      mean, 154.
    Solstice, summer, 176.
      winter, 181.
    Sound waves, 125.
    South Pole, 26.
    Spectroscope, 189.
      how made, 191.
    Spectrum, 133.
      solar, 189.
    Spring, 74.
    Spyglass, 136.
      stars seen through, 144.
    Standard meridians, 86, 156.
    Standard time, 155.
      zone system of, 156.
    Standard time meridians in United States, 159.
    Starcraft, merit badge for, 193.
    Star finder, how to make a, 1.
      Kullmer, 209.
    Star tests for eyesight, 197.
    Star time, 160.
    Star trails, how to make, 187.
    Stars, colored, 202.
      constellations having first magnitude, 201.
      double, 204.
      first magnitude, 200.
      how made, 119.
      how they shine, 121.
      invisible or dark, 206.
      magnitude of, 199.
      near the Sun’s path, 62.
      photographing, 185.
      seeing, 121.
      through a telescope, 149.
      variable, 205.
      what they are made of, 188.
      of the Zodiac, 166.
    Straight line defined, 194.
    Summer, 75.
    Summer solstice, 176.
    Sun, annular eclipse of the, 87.
      arctic, 87.
      attraction of, illustrated, 59.
      brightest star, 29.
      hot gases of, 121.
      chromosphere of, 32.
      core of, 32.
      corona of, 33.
      cross section of, 34.
      eclipse of, by the Moon, 110.
      how to see, 29.
      layers of flame of, 31.
      lighting a fire with, 37.
      from the Moon, view of, 104.
        stars near the, 62.
      partial eclipse of the, 112.
      path of the, 46, 170.
      photographing the, 187.
      photosphere of, 32.
      positions of planets round the, 54.
      prominences of, 31.
      rays of, signalling with, 38.
      shooting the, 84.
      surface of, 32.
      time marked by, 151.
      through a telescope, 148.
      weather and, 34.
      what it is made of, 30.
    Sun dial, how to make a simple, 42.
    Sun spots, 31.
      effects of, on the Earth, 33.
    Sun time, 152.
      how to set, 153.
      imaginary, 155.
    Sword of Orion, 22.

    Tangent defined, 58, 194.
    Taurus, Aldebaran in, 26.
      constellation of, 24, 63, 175.
      of the Egyptians, 26.
    Telescope, 136.
      astronomical, 138.
      with convex lenses, 142.
      defined, 136.
      discovery of, 136.
      equatorial, 188.
      how to make a cheap, 140.
      how to make a pinhole, 138.
      how it works, 139.
      kinds of, 137, 139.
      magnifying power of, 143.
      Mars through a, 149.
      Mercury through a, 148.
      Moon through a, 144.
      Neptune through a, 149.
      opera glass, 141.
      pinhole, 30.
      planets through a, 148.
      Saturn through a, 149.
      seeing the stars through a, 144.
      of sextant, 84.
      simple, 140.
      stars through a, 149.
      Sun through a, 148.
      Uranus through a, 149.
      Venus through a, 148.
    Telescope lens, mounting for, 140.
    Test for eyesight, Alcor, 11.
    Tides, high and low, 100.
      how the Moon makes, 99.
      spring and neap, 101.
    Time, apparent, 152.
      at different cities, 161.
      by the Moon, telling, 105.
      by the stars, 160.
      central, 160.
      to change star, into solar, 163.
      correct, 161.
        how obtained, 162.
      distributed by telegraph, 161.
        by wireless, 161.
      eastern, 158.
      equation of, 155, 207.
      Greenwich, 86.
      how sent by telegraph, 163.
      how to tell, by the Big Dipper, 12.
      imaginary Sun, 155.
      local, 86, 155.
      marked by the Moon, 151.
        by the Sun, 151.
      mean, 152.
        solar, 154.
      mountain, 160.
      o’ day, 151.
      Pacific, 160.
      railroad, 156.
      standard, 155.
      Sun, 154.
      what is it? 151.
      zone system of standard, 156.
    Time ball, how made and worked, 164.
    Time meridians in United States, standard, 159
    Total eclipse of the Sun, 110.
    Transit of a star, 162.
    Transit instrument, 162.
    Trapezium defined, 20, 21.
    True North Pole, 76.
    Tycho on the Moon, 144.

    Umbra of the Moon, 135.
    Uranus, Herschel’s planet, 47, 53.
      seeing, 53.
      through a telescope, 149.
    Ursa Major, constellation of, 6.
    Ursa Minor, constellation of, 16.

    Vanishing Man in the Moon, 146.
    Variable stars, 205.
    Venus, 47, 61.
      phases of, 50.
      seeing, 50.
      through a telescope, 148.
    Vernal equinox, 178.
    Vertical line defined, 194.
    Vesta, an asteroid, 54.
    Vibrating atoms, 123.
    Vibrations of bell, number of, 125.
    Virgo, the Virgin, 177.
    Volcanoes, how they were made, 91.
      on the Moon, 91.

    Waves, air, 125.
      in the ether, 127.
      length of light, 123.
      sound, 125.
      speed of, 126.
      of water, experiment with, 124.
    Weather, forecasting, by the barometer, 35.
      by signs, 37.
    Weather, and the Moon, 105.
      Sun and the, 34.
    Winter, 74.
    Winter solstice, 181.
    Wireless, time distributed by, 161.
    Wireless receiving sets, 165.

    Zero meridian, 156.
    Zodiac, as invented by the ancients, 167.
      as we know it today, 167.
      constellations of, 168.
      experiment with a cardboard, 170.
      how to find the constellations of the, 169.
      signs of the, 168.
      stars of the, 166.
      what it is, 166.
    Zone system of standard time, 156.