CELESTIAL EVOLUTION.
In the second chapter we outlined the nebular hypothesis as propounded
by Herschel. Some time earlier the French mathematician, Laplace, had
put forward his theory of the evolution of the Solar System. _Pierre
Simon Laplace_ was born at Beaumont-en-Auge, near Honfleur, in 1749, and
was educated in the Military School of his native town. In 1767 he
became Assistant Professor of Mathematics at Beaumont, and some years
later at the Military School in Paris, which position he retained for
many years. Member of the Institute and Minister of the Interior under
Napoleon, he was created a Marquis by Louis XVIII., and died at Arcuile
on March 5, 1827.
In the last chapter of his popular work, the ‘Système du Monde,’ Laplace
put forward his nebular theory “with that distrust which everything
ought to inspire that is not the result of observation or calculation.”
Laplace noticed that in the Solar System all the planets revolved round
the Sun in the same direction, from west to east, and that the
satellites of the planets obeyed the same law. He also observed that the
Sun, Moon, and planets rotated on their axes in the same direction as
they revolved round the Sun; also that the planets moved round the Sun,
and the satellites round their primaries, in almost the same plane as
the Earth’s orbit, the plane of the ecliptic. It was evident that these
remarkable congruities were not the result of chance, and accordingly
Laplace expressed his belief that the Solar System originated from a
great nebula, which in condensing detached various rings in the process
of rotation. These rings condensed into the various planets and their
satellites.
Laplace’s theory was powerfully supported by Herschel’s observations of
the various nebulæ in the heavens. But, with the supposed resolution of
the various nebulæ after the erection of the Rosse reflector in 1845,
the evidence in favour of the nebular theory seemed to be greatly
reduced. In 1864, however, the discovery of the gaseous nebulæ, by means
of the spectroscope, gave further support to the theory. Powerful aid
was lent to the nebular hypothesis by the famous German physicist,
_Hermann Ludwig Ferdinand von Helmholtz_ (1821-1894), in 1854, in his
theory of the maintenance of the Sun’s heat. Many theories had been
already advanced to account for this. After the discovery of the
conservation of energy, _Julius Robert Mayer_, one of the discoverers,
put forward the theory that the Solar heat was sustained by the inflow
of meteorites from space, and this idea was developed in 1854 by Sir
_William Thomson_, now _Lord Kelvin_ (born 1824), but it was soon
apparent that the supply of meteors required to sustain the Solar heat
was such as would have increased the mass of the Sun very considerably.
Accordingly the hypothesis was partially abandoned, and was succeeded by
that of Helmholtz, who pointed out that the radiation of the Sun’s heat
was the result of its contraction through cooling. The rate was then
estimated at 380 feet yearly, or a second of arc in 6000 years. This
theory was at once generally accepted. It assumes the Sun to be still
contracting, and therefore, on going backwards in imagination, we reach
a period when the Sun must have been much larger than now, and, in fact,
extended beyond the orbit of Neptune.
Several objections to Laplace’s nebular theory were urged by various
investigators. Among these was the retrograde motions of the satellites
of Uranus and Neptune, and the extremely rapid revolution of the inner
satellite of Mars. Other objections were urged by Babinet, Kirkwood, and
others, and at length a sweeping reform of the nebular theory was
proposed by Faye in 1884, in his work, ‘Sur l’Origine du Monde.’ Faye
put forward the idea that all the planets interior to the orbit of
Uranus were formed inside the solar nebula, while Uranus and Neptune
came into existence after the development of the Sun was far advanced.
But the objections to Faye’s theory are formidable, and the hypothesis
has not been accepted.
A popular exposition of the nebular theory was given in 1901 in Ball’s
work on ‘The Earth’s Beginning.’ He exhaustively discusses the whole
question, and explains the retrograde motion of the satellites of Uranus
and Neptune as due to the fact that the planes of the orbits of the
satellites will eventually be brought to coincide with the ecliptic.
These motions, says Ball, do not disprove the nebular theory. “They
rather illustrate the fact that the great evolution which has wrought
the Solar System into its present form has not finished its work: it is
still in progress.”
The theory that the Sun’s heat was maintained by meteors, was extended
by Proctor in 1870 to explain the growth of the planets through meteoric
aggregation as well as nebular condensation. Certainly the theory, as
developed by Proctor, accounted fairly well for the various features of
the Solar System; but the highest development of the meteoritic theory
is due to Lockyer, who published his views in 1890, in his work, ‘The
Meteoritic Hypothesis.’ Lockyer claims that his views are merely
extensions of Schiaparelli’s ideas regarding the concentration of
celestial matter. He considered the chief nebular line to be identical
with the remnant of the magnesium fluting, which is conspicuous in
cometic and meteoric spectra; but Huggins and Keeler, with more powerful
instruments, disproved the supposed coincidence. Lockyer considers that
“all self-luminous bodies in the celestial space are composed either of
swarms of meteorites or of masses of meteoric vapour produced by heat.
The heat is brought about by the condensation of meteor swarms, due to
gravity, the vapour being finally condensed into a solid globe.”
Lockyer divided the stars into seven groups, according to temperature,
the order of evolution being from red stars through a division of
second-type stars to Sirian stars, regarded as the hottest stars;
through a second division of solar stars to fourth-type stars. In fact,
the theory aspires to give a complete explanation of all celestial
phenomena, from meteors to nebulæ. Newcomb, however, considers that the
objections to the theory are insuperable, and his opinion is shared by
the majority of astronomers, many of whom, however, consider that there
are elements of truth in the theory; but Lockyer undoubtedly carried his
ideas to an extravagant extent.
Lockyer’s evolutionary order of the stars is not supported by Vogel.
Zöllner suggested in 1865 that yellow and red stars are simply white
stars in a further stage of cooling; but Angström showed that
atmospheric composition is a safer criterion of age than colour. Vogel’s
classification, first published in 1874, and further developed in 1895,
is from the standpoint of evolution. He considers Orion stars and Sirian
stars to be the youngest orbs. Solar stars are considered by Vogel to
have wasted much of their store of radiation, and red stars are viewed
as “effete suns, hastening rapidly down the road to final extinction.”
He considers stars of Secchi’s fourth type to be also dying suns, both
types representing alternative roads for stars of the Solar type in
their decline into dark stars. This view is supported by Dunér, and is
distinctly confirmed by Hale’s observations with the Yerkes telescope.
Vogel’s views, in fact, are generally accepted among astronomers. The
nebular theory, modified by subsequent research, seems destined to hold
its own against all attacks.
Distinctly supplementary to the nebular theory are the remarkable
researches, commenced in 1879, by Sir _George Howard Darwin_ (born
1845), son of Charles Darwin the great biologist. George Howard Darwin
was born in 1845, at Downe in Kent, was educated at Cambridge, and
studied for the law; but in 1873 he returned to Cambridge, where he
became Plumian Professor of Astronomy in 1883. In 1879 he communicated
to the Royal Society the first of his papers on tidal friction, which
were summed up in his book on ‘The Tides,’ published in 1898. He finds
that the tides act upon the Earth as a brake does upon a machine,—they
tend to retard its rotation. Consequently, the day is growing longer,
the Moon’s orbit is becoming enlarged, and its period of revolution is
being lengthened.
At present the day is about twenty-four hours long, and the month about
twenty-seven days. The day, however, will be lengthened at a more rapid
rate than the month, and in the remote future the day and month will
both last fifty-five of our present days. The Moon will revolve round
the Earth in the same period that the Earth rotates on its axis, and the
two bodies will perform their circuit round the Sun as if united by a
bar.
Not only can we foresee the future of the Earth-Moon System, but we can
also read the past. According to Darwin’s theory, the Earth, in the
remote past, was probably rotating on its axis in a very short period,
between three and five hours. The Moon must then have been much nearer
us than it is now, and was probably revolving round its primary in the
same period that the Earth took to rotate on its axis. The two globes,
then gaseous, must have been revolving almost in actual contact. Had the
month been even a second shorter than the day, the Moon must inevitably
have fallen back on the Earth. As it was, the condition of affairs could
not endure. The condition of the Moon resembled that of an egg balanced
on its point. The Moon must either recede from the Earth or fall back
upon it. The solar tide here interfered, and caused the Moon to recede
from its primary until it reached its present distance of 239,000 miles.
The fact that the Earth and Moon were almost in contact suggests that
they were probably in contact. In other words, the Moon originally
formed part of the Earth, which, in consequence of its short-rotation
period, and probably also owing to the interference of the solar tide,
split into two portions, and the smaller of these now forms the Moon. It
is likely that the matter now forming the Moon was detached from the
Earth in separate particles. Just as the tides raised by the Moon tend
to retard the motion of the Earth, so the Earth tides raised in the Moon
have already done their work. The Moon now rotates on its axis in the
same time as it revolves round the Earth. Part of the evolution of the
Earth-Moon system is completed. Schiaparelli’s discovery that the
rotation periods of both Venus and Mercury coincide with their times of
revolution is distinctly confirmatory of Darwin’s theory.
In his chapter on the “Evolution of Celestial Systems” in his book on
‘The Tides,’ Darwin discusses the distribution of the satellites of the
Solar System. He says of the evolution of a planet: “We have seen that
rings should be shed from the central nucleus when the contraction of
the nebula has induced a certain degree of augmentation of rotation.
Now, if the rotation were retarded by some external cause, the genesis
of a ring might be retarded or entirely prevented.” He then remarks that
probably the formation of the Moon was retarded, and in the case of
Mercury and Venus, solar tidal friction prevented satellite formation.
This explains why Mercury and Venus have no satellites, the Earth only
one, Mars two, while the exterior planets have each several satellites.
The theory of tidal friction was extended in 1892 to the explanation of
the double stars by the American astronomer, See. See showed by
mathematical calculation the effects of tidal friction in shaping the
eccentric orbits of the binary stars, the course of evolution being
traced from double stars, revolving almost in contact, which the
spectroscope reveals, to the telescopic doubles. See’s researches have
done much to supplement those of Darwin, who considers that there are
two types of cosmical evolution,—the Laplacian, and the “second” or
lunar type.
Lowell, in his work on ‘The Solar System’ (1903), adds six congruities
to those remarked by Laplace and his successors. These are, “All the
satellites turn the same face to their primaries (so far as we can
judge); Mercury, and probably Venus, do the same to the Sun; one law
governs position and size in the Solar System and in all the satellite
systems; orbital inclinations in the satellite systems increase with
distance from the primary; the outer planets show a greater tilt of axis
to orbit-plane with increased distance from the Sun (so far as
detectable); the inner planets show a similar relation.”
The fate of the average solar star is sketched out by Vogel’s
classification, and by any evolutionary hypothesis which we may adopt.
In the words of Lowell: “Though we cannot as yet review with the mind’s
eye our past, we can, to an extent, foresee our future. We can with
scientific confidence look forward to a time when each of the bodies
composing our Solar System shall turn an unchanging face in perpetuity
to the Sun. Each will then have reached the end of its evolution set in
the unchanging stare of death. Then the Sun itself will go out, becoming
a cold and lifeless mass; and the Solar System will circle unseen,
ghostlike, in space, awaiting only the resurrection of another cosmic
catastrophe.”
As to what this cosmic catastrophe will be, science gives no definite
idea; nor can astronomers say with certainty whether the Universe will
come to an end by the extinction of its luminaries, or whether the suns
and planets will be brought back to luminosity again; but the human mind
shrinks from the idea of a dead Universe. At this point science has said
its last word, and must give place to religion. In our day we may repeat
with deeper meaning the words of the Scottish astronomer, Thomas Dick:
“Here imagination must drop its wing, since it can penetrate no further
into the dominions of Him who sits on the Throne of Immensity.
Overwhelmed with a view of the magnificence of the Universe, and of the
perfections of its Almighty Author, we can only fall prostrate in deep
humility and exclaim, ‘Great and marvellous are Thy works, Lord God
Almighty.’”
INDEX.
A
Absolute parallax, 158.
Adams, J. C., 78, 116, 117, 118, 119, 120, 140.
Adams, W., 205.
Aerolites, 147, 148, 149.
Airy, Sir G. B., 27, 104, 117, 120.
Aitken, R. G., 202.
Alcyone (η Tauri), 217.
Aldebaran (α Tauri), 151, 166, 170, 172.
Algol (β Persei), 178, 182, 183, 184, 193, 204.
Al-Sufi, 180, 183.
Altair (α Aquilæ), 170.
Anderson, T. D., 191, 192.
Andromeda nebula, 180, 208.
Andromedæ (γ), 201.
Andromedæ (Nova), 180.
Andromedid meteors, 142, 149.
Angström, A. J., 50, 51.
Antares (α Scorpii), 171.
Aquila, 195.
Aquilæ (η), 185, 186.
Arago, F. J. D., 6, 11, 31, 37, 40, 118, 120, 129.
Arcturus (α Bootis), 165, 170.
Arequipa Observatory, 75.
Argelander, F. W. A., 27, 159, 167, 178, 179, 180, 218.
Argo Navis, 221.
Argus (η), 187, 188.
Armagh Observatory, 206.
Asteroids, 19, 62, 97-102.
Astronomer-Royal of Scotland, 134, 155, 191;
of England, 59, 17;
of Ireland, 151, 156.
Astronomy of the invisible, 203.
Aurigæ (Nova), 191, 192, 195.
Auwers, A., 167, 188, 203.
B
Babinet, 230.
Baily, F., 159.
Bakhuyzen, H. G., 91.
Ball, Sir R. S., 23, 34, 108, 141, 149, 156, 158, 230.
Barnard, E. E., 19, 95, 107, 108, 110, 111, 113, 136, 191, 211.
Beer, W., 68, 69, 90.
Bellatrix (γ Orionis), 209.
Bélopolsky, A., 87, 110, 166, 185, 186, 204, 205.
Berlin Observatory, 119, 120.
Bessel, F. W., 24, 82, 116, 151, 152, 153, 154, 159, 167, 202,
203.
Betelgeux (α Orionis), 165, 171, 172, 182, 187.
Biela, W., 128.
Biela’s comet, 128, 129, 142, 143, 146, 149.
Birmingham, J., 189.
Bode, J. E., 97, 98, 152.
Bode’s Law, 97.
Boeddicker, O., 77.
Bond, G. P., 103, 109, 130, 136, 207.
Bond, W. C., 109, 112, 120.
‘Bonn Durchmusterung,’ 159, 160, 218.
Bonn Observatory, 88, 97, 160.
Böotis (ε), 30.
Borisiak, 192.
Boss, L., 168.
Bouvard, A., 115, 116.
Bradley, J., 159, 167.
Brédikhine, T. A., 105, 131, 132, 133, 134, 135.
Brewster, Sir D., 50, 101, 178.
Brinkley, J., 151.
Brünnow, F., 156.
Bruno, G., 35.
Buffon, 103.
Bunsen, R. W., 51.
Burchell, 188.
Burnham, S. W., 201, 202, 212.
C
Callandreau, O., 136.
Callandrelli, 151.
Cambridge Observatory, 116.
Campbell, T. (Poet), 2.
Campbell, W. W., 24, 107, 110, 166, 168, 187, 191, 193, 204, 205.
Canals of Mars, 91, 92, 93, 94, 95.
Cancri (ζ), 206.
Cancri (S), 180.
Canis Major, 188.
‘Cape Durchmusterung,’ 161, 162.
Cape Observatory, 155, 157.
Capella (α Aurigæ), 170, 176, 193, 205.
Carnera, L., 100.
Carpenter, J., 73.
Carrington, R. C., 45, 46, 59.
Cassini, D., 21.
Cassiopeia, 221.
Castor (α Geminorum), 30, 200, 205.
Celoria, G., 202, 218, 221, 223, 224.
Centauri (α), 155, 188, 225.
Centaurus, 221.
Cephei (δ), 178, 182, 185, 186.
Cepheus, 221.
Ceres, 19, 98, 101.
Cerulli, V., 86, 91, 94.
Chacornac, 161.
Challis, J., 116, 119, 120.
Chambers, G. F., 31.
Chandler, S. C., 88, 89, 181, 184.
Chladni, E., 138.
Chromosphere, solar, 55, 56.
Clark, A., 202.
Clerke, Miss A. M., 3, 5, 8, 12, 13, 15, 25, 26, 34, 42, 58, 75,
86, 92, 105, 109, 124, 125, 131, 132, 133, 140, 142, 169,
186, 187, 189.
Clerk-Maxwell, J., 109, 110.
Coggia’s comet, 131, 132, 133.
Comet families, 135.
Comets, 24, 123-137, 141, 142, 143, 144, 146, 149, 152.
Common, A. A., 107, 209.
Copeland, R., 134, 135, 190, 208.
Cornu, A., 189.
Corona Borealis, 188.
Corona, solar, 55, 57, 64.
Coronæ (Nova), 188, 189.
Crossley, E., 211.
Crux, 221.
Cygni (61), 152, 158.
Cygni (Y), 184, 185.
Cygni (Nova), 189, 190.
Cygnus, 152, 189, 221.
D
Damoiseau, 78.
D’Arrest, H. L., 96, 119, 142, 212.
Dartmouth Observatory, 56.
Darwin, Sir G. H., 233, 234, 235, 236.
Dawes, W. R., 90, 117.
De la Rue, W., 52, 75.
Delaunay, C. E., 78, 79.
Dembowski, E., 201.
Deneb (α Cygni), 165.
Denning, W. F., 84, 85, 91, 95, 105, 111, 112, 144, 145, 146.
Deslandres, H., 110.
Dick, T., 85, 238.
Disc-theory, 32, 36, 38, 39, 214, 218.
Di Vico, F., 85, 86, 170.
Doberck, W., 201.
Donati, G. B., 130, 131, 169.
Donati’s comet, 130, 133, 136.
Doppler, C., 57, 58.
Doppler’s Principle, 58, 59, 87, 110, 165, 168, 203.
Douglass, A. E., 92, 107.
Draconis (λ), 182.
Draper, H., 136, 172, 175.
Dreyer, J. L. E., 206.
Dunecht Observatory, 157.
Dunér, N. C., 58, 59, 174, 175, 181, 184, 185, 201, 202, 233.
Dunkin, E., 27, 167.
Dunsink Observatory, 156.
E
Earth, 76, 97, 103, 104, 147, 148, 149, 153, 154, 156, 236.
Earth-Moon system, 234, 235.
Easton, C., 221.
Eclipses, lunar, 77.
Eclipses, solar, 56, 57, 80, 81.
Edinburgh (Royal) Observatory, 195.
Electrical repulsion theory, 126.
Elger, T. G., 74.
Elkin, W. L., 157.
Encke, J. F., 30, 61, 119, 127, 128, 216.
Encke’s comet, 127, 128, 137.
Erman, 140.
Eros, 62, 101.
Ertborn, 85.
Euler, L., 88, 89.
Evolution, planetary, 228, 229, 230, 231.
Evolution, stellar, 33, 34, 231, 232.
F
Faye, H., 60, 129, 230.
Faye’s comet, 129, 137.
Ferguson, J., 9, 178.
Flammarion, C., 87, 91, 95, 121, 147, 164, 187, 195, 201, 202,
226.
Flamsteed, J., 5.
Fleming, Mrs, 192, 195.
Forbes, G., 122.
Fraunhofer, J. 47, 48, 49, 50, 3, 151, 153, 169.
Fraunhofer lines, 48, 49, 50, 51, 169, 172.
Frost, E. B., 205.
G
Galactic poles, 35, 224.
Galaxies, external, 32, 218, 225, 226.
Galaxy, or Milky Way, 32, 36-42, 186, 211, 215, 216, 217, 219,
220, 221, 224, 225.
Galileo, 44, 107.
Galle, J. G., 62, 108, 109, 119, 142.
Galloway, T., 167.
Gambart, 128.
Gauss, C. F., 27, 98, 167.
Gautier, A., 45.
Gemini, 11, 194.
Geminorum (Nova), 194.
Geminorum (ζ), 180, 182, 185.
George III., 11, 23.
Gill, Sir D., 62, 136, 155, 157, 160, 161, 221.
Glasgow Observatory, 216.
Goodricke, J., 178, 183.
Gore, J. E., 24, 38, 179, 181, 182, 183, 192, 202, 215, 220, 225,
226.
Gould, B. A., 135, 160, 163, 180, 220, 221.
Grant, R., 216.
Gravitation, law of, 29.
Greenwich Observatory, 59, 117.
Grimmler, 192.
Groombridge (1830), 156, 162, 223.
Groombridge (1618), 156.
Gruithuisen, 87.
H
Hale, G. E., 55, 57, 233.
Hall, A., 96, 111, 112, 156, 190.
Hall, Maxwell, 121.
Halley, E., 138.
Halley’s comet, 123, 130, 152.
Halm, J., 195, 196.
Hansen, P. A., 61, 78, 79.
Hansky, A., 57.
Harding, K. L., 99, 153, 220.
Hartwig, E., 190.
Harvard Observatory, 174, 175, 191.
Hasselberg, B., 148, 190.
Heis, E., 179, 220.
Heliometer, 153, 157.
Helium stars, 174.
Helmholtz, H., 61, 229.
Hencke, K. L., 99.
Henderson, T., 154, 155.
Henry, Paul and Prosper, 100, 114, 210.
Hercules, 167.
Herculis (α), 182.
Herculis (λ), 26.
Herschel, William, 1-42, 43, 60, 63, 65, 69, 74, 77, 85, 90, 99,
103, 109, 111, 112, 115, 123, 150, 162, 167, 176, 196,
197, 207, 214, 216, 218, 224, 227.
Herschel, A., 144.
Herschel, Caroline, 6, 8, 9, 12, 13, 14, 30, 35, 127, 198.
Herschel, Sir J., 4, 17, 27, 30, 37, 50, 112, 113, 120, 130, 144,
167, 187, 188, 197, 198, 199, 200, 214, 215.
Hind, J. R., 99, 129, 135, 180, 188.
Hoek, 135.
Holden, E. S., 191.
Hough, G., 105.
Houzeau, J. C., 220.
Huggins, Lady, 172.
Huggins, Sir W., 54, 57, 74, 95, 106, 114, 131, 136, 165, 170,
171, 172, 173, 189, 190, 191, 193, 195, 207, 208, 212,
231.
Humboldt, A., 44, 139.
Hussey, W. J., 116, 201.
I
Innes, R., 188.
Intra-Mercurial planet, 80, 81.
Italian spectroscopists, 54, 55.
J
Janssen, P. J. C., 52, 53, 54, 57, 59, 112, 209.
Juno, 19, 99, 101.
Jupiter, 20, 75, 97, 101-108, 112, 114, 121, 122, 135, 144, 146.
Juvisy Observatory, 164.
K
Kaestner, 65, 124.
Kaiser, F., 90.
Kant, I., 34, 35, 101, 103.
Kapteyn, J. C., 27, 158, 161, 162, 168, 221, 222.
Keeler, J. E., 95, 114, 185, 208, 211, 212, 213, 231.
Kelvin, Lord, 229.
Kempf, P., 181.
Kepler, J., 5, 35, 137.
Kirchoff, G. R., 61, 169, 172.
Kirkwood, D., 140, 230.
Klein, H. J., 73.
Klinkerfues, E., 142, 202.
Konkoly, N., 175.
Küstner, F., 88.
L
Lalande, 23, 152.
Lambert, J. H., 34.
Lamont, J., 44.
Langley, S. P., 77.
Laplace, P. S., 20, 33, 34, 77, 109, 148, 152, 195, 227, 228, 229.
Lassell, W., 112, 115, 117, 120.
Latitude, variation of, 88, 89.
Leipzig Observatory, 173.
Leonid meteors, 139, 140, 142.
Leonis (β), 183.
Lescarbault, 80.
Le Verrier, U. J. J., 61, 80, 81, 118, 119, 120, 142, 164.
Leyden Observatory, 91.
Libræ (δ), 180.
Lick Observatory, 93, 107, 166, 168, 191, 213.
Light, extinction of, 40, 215, 216, 224, 225.
Lindsay, Lord, 157.
Linné, 71, 72.
Lockyer, Sir J. N., 52, 53, 54, 55, 58, 149, 174, 191, 193, 195,
208, 209, 231, 232.
Lockyer, W. J. S., 210.
Loewy, M., 75.
Lohrmann, W. G., 68, 71.
Lohse, W. O., 88, 105.
Loomis, 188.
Lowell, P., 83, 84, 86, 87, 91, 92, 93, 94, 122, 236, 237.
Lowell Observatory, 92, 94, 106, 114.
Lund Observatory, 59.
Lupus, 221.
Luther, R., 100.
Lyra, 221.
Lyra (β), 178, 182, 185.
Lyrid meteors, 122.
M
Maclaurin, C., 9.
Maclear, Sir T., 155.
Mädler, J. H., 27, 68, 69, 71, 96, 104, 202, 203, 216, 217, 218.
Magellanic clouds, 219.
Magnetism, 44, 60.
Mars, 18, 19, 90-97, 101, 144, 236.
Maunder, E. W., 59, 60, 94, 95, 134, 145, 166, 224.
Mascari, A., 86.
Mayer, C., 164.
Mayer, J. R., 229.
Mazapil meteorite, 149.
Méchain, 127.
Mee, A., 68.
Melloni, 76.
Mercury, 18, 80, 81-84, 97, 236.
Messier, C., 30.
Meteorites, 147, 148, 149, 229, 231.
‘Meteoritic Hypothesis,’ 231, 232.
Meteors, 138-149.
Meudon Observatory, 59.
Milan Observatory, 82, 202, 224.
Milky Way. See Galaxy.
Miller, W. A., 50, 172.
Mira Ceti, 11, 182, 186, 187.
Mitchel, O. M., 31.
Mizar (ζ Ursæ Majoris), 204.
Möller, A., 129.
Moon, the, 10, 24, 65-79, 90, 95, 148, 228.
Moscow Observatory, 132.
Mouchez, A., 161.
Müller, G., 175, 181.
Munich Observatory, 44, 224.
N
Napoleon, 67, 127.
Nasmyth, J., 73, 103.
Nebulæ, 30, 31, 207-213, 228.
Nebular Hypothesis, 33, 195, 227, 228, 229, 230, 233.
Neison (Nevill), E., 73.
Neisten, 86, 105.
Neptune, 120, 121, 135, 229, 230.
Newall, H. F., 205.
Newcomb, S., 27, 64, 78, 89, 94, 162, 168, 220, 222, 223, 224,
232.
Newton, H. A., 140, 141.
Newton, Sir I., 2, 17, 29, 77.
Nichol, J. P., 31, 207.
Nordvig, L., 192.
O
Olbers, H. W. M., 19, 20, 69, 98, 99, 123, 124, 125, 126, 127,
129, 130, 139, 148, 152, 153.
Olbers’ comet, 125.
Olmsted, D., 138, 207.
Ophiuchi (α), 183.
Orion, 221.
Orion nebula, 10, 33, 207, 208, 209, 213.
Orion stars, 174, 193, 209, 232.
Orionis (κ), 209.
Orionis (η), 209.
Orionis (θ), 209.
Orionis (U), 181, 182, 186, 187.
P
Palisa, J., 100.
Pallas, 19, 99, 101.
Parallax, solar, 61, 62, 63, 101.
Parallax, stellar, 150-158, 190.
Paris Congresses, 161.
Paris Observatory, 78, 118, 171.
Perrine, C. D., 81, 108, 194.
Perrine’s comet, 136.
Perrotin, H., 86, 91, 100, 114.
Peck, W., 162.
Persei (Nova), 192, 193, 194, 195.
Perseid meteors, 122, 141.
Perseus, 192, 221.
Peters, C. H. F., 100.
Peters, C. A. F., 142, 153, 155, 202.
Photography, astronomical, 54, 56, 57, 59, 75, 81, 94, 108, 113,
136, 158, 160, 161, 172, 175, 192, 193, 194, 203, 208,
209, 210, 211, 212.
Photometry, 176, 177.
Piazzi, G., 19, 20, 98, 150.
Pickering, E. C., 174, 175, 176, 177, 181, 182, 183, 185, 193,
194, 203, 204, 220, 221.
Pickering, W. H., 75, 76, 81, 91, 92, 93, 107, 113, 209.
Plana, G., 78, 79.
Pleiades, 124, 210, 217.
Pogson, N. R., 142, 180.
Pole Star, 205.
Pollux, 165, 170.
Pons, J. L., 127.
Pontécoulant, 79.
Potsdam Observatory, 46, 173, 176.
Pritchard, C., 158, 177.
Proctor, R. A., 4, 20, 38, 41, 90, 91, 104, 148, 163, 164, 218,
219, 220, 231.
Procyon (α Canis Minoris), 151, 203.
Prominences, solar, 52, 53, 55, 64.
Puiseux, P., 75.
Pulkowa Observatory, 200.
Q
Quetelet, A., 139.
R
Radiant points, meteoric, 139, 144, 145, 146.
Ranyard, A. C., 106, 146.
Red spot on Jupiter, 105, 106.
Regulus (α Leonis), 164, 165.
Relative parallax, 157.
Réseau, Photospherique, 59.
Resisting medium, 128.
Respighi, L., 55.
Reversing layer, 56, 57.
Ricco, A., 87, 105.
Rigel (β Orionis), 165, 209.
Ritchey, G., 194.
Roberts, A. W., 181.
Roberts, I., 209, 210.
Roche, E., 109.
Roman College Observatory, 85.
Rosse, third Earl of, 141, 156, 207, 208, 218.
Rosse, fourth Earl of, 77.
Rotation of the Sun, 58, 59;
of the planets, 82, 83, 84, 85, 86, 87, 104, 111, 112.
Rowland, H. A., 52.
Rutherfurd, L. M., 75, 169.
S
Sabine, Sir E., 44.
Safford, T. H., 202.
Santini, G., 159.
Savary, F., 30, 199.
Satellites, 96, 107, 108, 112, 113, 115, 120, 121, 236.
Saturn, 20, 21, 22, 97, 103, 108-113, 121, 135.
Schaeberle, J. M., 93, 107, 191, 203.
Scheiner, C., 44.
Scheiner, J., 166, 174, 176.
Schiaparelli, G. V., 82, 83, 84, 85, 86, 87, 91, 92, 114, 141,
143, 149, 201, 220, 224, 231, 235.
Schjellerup, H., 180.
Schmidt, J. F. J., 69, 70, 71, 72, 73, 104, 179, 180, 189.
Schönfeld, E., 160, 179, 180, 188, 189.
Schröter, J. H., 16, 65, 66, 67, 68, 69, 70, 74, 81, 82, 84, 85,
86, 87, 97, 99, 153.
Schwabe, S. H., 18, 43, 44, 46, 55.
Schwassman, A., 100.
Secchi, A., 52, 54, 55, 60, 72, 90, 114, 141, 170, 171, 173.
Secchi’s types of stellar spectra, 170, 171, 173, 174, 175, 189,
232.
See, T. J. J., 201, 202, 236.
Seeliger, H., 110, 195, 196, 202, 206, 224, 225.
Serviss, G. P., 158.
Sirius (α Canis Majoris), 151, 170, 173, 188, 202, 225.
Slipher, V. M., 106, 114, 204.
Sime, J., 27.
Sola, J. C., 112.
Solar cluster, 221, 222.
Solar system, motion of, 26, 27, 167, 168.
South, Sir J., 198.
Spectroscopic binaries, 203, 204, 205.
Spencer, H., 218.
Spica (α Virginis), 204.
Spörer, F. W. G., 45, 46, 54, 59.
Star-catalogues, 159, 160, 161, 162.
Star-clusters, 30, 31, 32, 206, 210.
Star-drift, 164.
Star-gauging, 36, 40, 41, 224.
Stars, distance of, 150-158.
Stars, distribution of, 35, 39, 40, 198-214.
Stars, double, 28, 29, 30, 197-206.
Stars, gaseous, 171, 174.
Stars, proper motion of, 162, 163, 164, 165.
Stars, radial motion of, 165, 166.
Stars, temporary, 156, 182, 188-196.
Stars, triple and multiple, 206.
Stars, variable, 177-188.
Stellar spectra, 169-176, 187, 189, 190, 191, 193, 194.
Stellar universe, 35-42, 214, 215-226.
Stereo-comparator, 100, 101.
Stokes, Sir G., 50.
Stone, E. J., 157, 160.
Stroobant, P., 88.
Struve, F. G. W., 3, 37, 38, 40, 42, 128, 151, 153, 200, 214, 215,
216, 218.
Struve, H., 201.
Struve, L., 27, 163, 167.
Struve, O. W., 27, 110, 115, 120, 153, 156, 163, 200, 201.
Stumpe, O., 167.
Sun, 15, 16, 17, 40, 43-64, 65, 80, 81, 105, 125, 128, 170, 222,
228, 229, 230, 237.
Swift, L., 81.
Swift’s comet, 136.
T
Tacchini, P., 55, 86, 87.
Taurus, 217, 221.
Tempel, E., 210.
Tennyson, 96.
Tidal friction, 79, 87, 233, 234, 235, 236.
Tisserand, F. F., 146.
Todd, D. P., 122.
Trans-Neptunian planet, 121, 122.
Trouvelot, E., 86, 87.
Tschermak, 148.
Tulse Hill Observatory, 171.
Turner, H. H., 194, 224.
Twining, A. C., 139.
U
Upsala Observatory, 59.
Uranometria Argentina, 160.
Uranus, 11, 20, 22, 23, 97, 113, 114, 115, 118, 121, 135, 141,
230.
Ursa Major, 162, 164.
Ursæ Majoris (δ), 182.
Ursæ Majoris (ξ), 199.
V
Venus, 18, 84-88, 97, 235, 236.
Venus, transits of, 61, 62, 87.
Vega (α Lyræ), 151, 165, 170, 172, 173.
Very, F. W., 77.
Vesta, 19, 99, 101, 102.
Vogel, H. C., 84, 88, 95, 102, 106, 114, 131, 148, 166, 173, 174,
175, 183, 184, 185, 190, 191, 193, 195, 204, 209, 232,
233, 237.
Vulcan, 81.
W
Washington Observatory, 96, 223.
Watson, J. C., 81, 100.
Webb, T. W., 72, 73, 104.
Weinek, L., 75.
Weiss, E., 142.
Well’s comet, 134.
Whewell, W., 218.
Williams, A. S., 110, 193.
Wilson, A., 16.
Winlock, J., 177.
Winnecke, F. A. T., 131.
Witt, K. G., 101.
Wolf, Max, 100, 181, 191, 194, 211.
Wolf, R., 44, 45, 188.
Wolf and Rayet, 171.
Wolf-Rayet stars, 171, 174.
Wollaston, W. H., 48.
Wright, T., 34, 110.
Y
Yale Observatory, 157.
Yerkes Observatory, 55, 111, 202.
Young, C. A., 54, 56, 57, 58, 60, 87, 114, 190.
Z
Zach, F. X., 97, 98, 152.
Zantedeschi, 77.
Zenger, 85, 88.
Zöllner, J. C. F., 54, 58, 60, 84, 103, 132, 232.
CORRIGENDA.
P. 30, l. 5, _for_ “objects” _read_ “orbits.”
P. 36, l. 13, _for_ “unable” _read_ “able.”
P. 61, l. 17, _for_ “8″.371” _read_ “8″.571.”
P. 63, l. 21, _for_ “bases” _read_ “gases.”
P. 100, l. 16, _for_ “Schwussmann” _read_ “Schwassmann.”
P. 167, l. 28, _for_ “Strumpe” _read_ “Stumpe.”
P. 184, l. 11, _for_ “star-variables” _read_ “variable stars.”
P. 199, l. 23, _for_ “2102” _read_ “1202.”
THE END.
PRINTED BY WILLIAM BLACKWOOD AND SONS.
Transcriber’s Notes
—Silently corrected a few typos, and incorporated the corrigenda into
the text.
—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—In the text versions only, text in italics is delimited by
_underscores_.