in its equation, hence this number of points specifically determine it.
But special points, like focus or vertex, count as two ordinary ones.
Hence three points plus the focus act as five points, and determine a
conic or curve of the second degree. Three observations therefore fix an
orbit round the sun.
[28] Its name suggests a measure of the diameter of the sun's disk, and
this is one of its functions; but it can likewise measure planetary and
other disks; and in general behaves as the most elaborate and expensive
form of micrometer. The Koenigsberg instrument is shewn in fig. 92.
[29] It may be supposed that the terms "minute" and "second" have some
necessary connection with time, but they are mere abbreviations for
_partes minutae_ and _partes minutae secundae_, and consequently may be
applied to the subdivision of degrees just as properly as to the
subdivision of hours. A "second" of arc means the 3600th part of a
degree, just as a second of time means the 3600th part of an hour.
[30] A group of flying particles, each one invisible, obstructs light
singularly little, even when they are close together, as one can tell by
the transparency of showers and snowstorms. The opacity of haze may be
due not merely to dust particles, but to little eddies set up by
radiation above each particle, so that the air becomes turbulent and of
varying density. (See a similar suggestion by Mr. Poynting in _Nature_,
vol. 39, p. 323.)
[31] The moon ought to be watched during the next great shower, if the
line of fire happens to take effect on a visible part of the dark
portion.
[32] Address to Birmingham Midland Institute, "A Glimpse through the
Corridors of Time."
INDEX
INDEX
A
Abbott, T.K., on tides, 369
Adams, John Couch, 193, 217, 302, 323, 324, 325, 327, 329, 330, 352, 385
Airy, Sir George, 193, 244, 302, 323, 324, 327, 367
Anaxagoras, 15
Appian, 218
Arabs, the, form a link between the old and new science, 9
Archimedes, 7, 8, 84, 87, 144, 177
Aristarchus, 34
Aristotle, 66, 69, 88, 94, 99, 167.
He taught that the earth was a sphere, 16;
his theories did not allow of the earth's motion, 34;
he was regarded as inspired, 89
B
Bacon, Francis, 142, 143, 144, 145.
His _Novum Organum_, 141
Bacon, Roger, 96, 139, 140.
The herald of the dawn of science, 9
Brahe, George, uncle of Tycho Brahe, 39
Brahe, Steno, brother of Tycho Brahe, 39
Brahe, Tycho, 37, 39, 40, 44, 45, 49, 51, 53, 54, 55, 58, 63, 64, 65, 66,
68, 71, 72, 74, 75, 77, 78, 86, 94, 117, 137, 155, 165, 166, 200, 244,
281, 288.
He tried to adopt the main features of the Copernican theory without
admitting the motion of the earth, 37;
he was a poor theorist but a great observer, 38;
his medicine, 44;
his personal history, 39, _seq._;
his observatory, Uraniburg, 47;
his greatest invention, 50, note;
his maniac Lep, 52;
his kindness to Kepler, 63
Ball, Sir R., 391, 394;
his _Story of the Heavens_, 377
Barrow, Dr., 165, 187
Bessel, 288, 310, 311, 313, 315, 316, 318, 323
Biela, 345, 346, 347
Bode's Law, 60, 296, 298, 299, 326
Boyle, 139, 188
Bradley, Prof. James, 233, 246, 247, 249, 252, 253, 308, 319
Bremiker, 328, 329
Brewster, on Kepler, 78
Brinkley, 308
Bruno, Giordano, 108, 127
C
Castelli, 112, 133
Cayley, Prof., 385
Challis, Prof., 328, 329
Clairut, 193, 216, 217, 219, 234, 341
Clark, Alvan and Sons, 316
Columbus, 9, 144
Copernicus, 7, 10, _seq._, 14, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38,
62, 66, 68, 70, 78, 93, 95, 100, 108, 111, 121, 122, 137, 155, 166, 223,
234, 247, 307;
his _De Revolutionibus Orbium Coelestium_, 11, 75, 138;
he _proved_ that the earth went round the sun, 13;
the influence of his theory on the Church, 13, _seq._;
his life-work summarised, 30;
his Life by Mr. E.J.C. Morton, 31
Copernican tables, 40;
Copernican theory, 59, 60, 125, 144, 167
Copernik, Nicolas; see Copernicus
Cornu, 238
Croll, Dr., his _Climate and Time_, 264
D
D'Alembert, 193, 234
Darwin, Charles, 134, 138, 397
Darwin, Prof. George, 367, 394
Delambre, 253
Descartes, 145, 146, 148, 151, 153, 156, 158, 164, 165, 167, 178, 181,
224, 227;
his _Discourse on Method_, 142;
his dream, 147;
his system of algebraic geometry, 149, _seq._;
his doctrine of vortices, 151, _seq._;
his _Principia Mathematica_, 154;
his Life by Mr. Mahaffy, 154
E
Earth, the difficulties in the way of believing that it moved, 34, _seq._
"Earth-rise in Moon-land," 258, note
Encke, 345, 346
Epicyclic orbits explained, 23, _seq._
Equinoxes, their precession discovered by Hipparchus, 27
Eudoxus, 19
Euler, 193, 234
F
Faraday, 84
Fizeau, 238, 239
Flamsteed, 215, 246, 284, 308, 319
Fraunhofer, 311
Froude, Prof.; his _Oceania_, 387
G
Galen, 87
Galileo, Galilei, 63, 75, 84, 88, 90, 92, 93, 97, 98, 101, 104, 106, 107,
108, 109, 110, 112, 114, 116, 117, 118, 120, 121, 122, 123, 125, 127,
133, 134, 137, 144, 145, 153, 154, 157, 165, 166, 167, 168, 177, 188,
200, 224, 227, 256, 281, 288, 309, 361;
his youth, 85;
his discovery of the pendulum, 86;
his first observations about falling bodies, 88, _seq._;
he invents a telescope, 95;
he adopts the Copernican theory, 94;
he conceives "earth-shine," 100;
he discovers Jupiter's moons, 103;
he studies Saturn, 114, _seq._;
his _Dialogues on the Ptolemaic and Copernican Systems_, 124;
his abjuration, 130;
he becomes blind, 132;
he discovered the Laws of Motion, 167, _seq._;
he guessed that sight was not instantaneous, 236, 237
Galle, Dr., 245, 329
Gauss, 299, 300
Gilbert, Dr., 139, 140, 157, 188;
his _De Magnete_, 140, 144
Greeks, their scientific methods, 7
Groombridge's Catalogue, 315
H
Hadley, 185
Halley, 192, 193, 194, 195, 197, 215, 218, 219, 246, 258, 260, 261, 340,
341;
he discovered the _Principia_, 194
Harvey, 144, 149
Haughton, Dr., 321;
his manual on Astronomy, 21, note
Heliometer, described, 311
Helmholtz, 378
Helmont, Van, invented the word "gas," 141
Henderson, 310, 314
Herschel, Alexander, 275, 277, 278, 279
Herschel, Caroline, 275, 276, 279, 286, 345;
her journal quoted, 277, _seq._;
her work with William H. described, 284
Herschel, Sir John, 283, 285, 327, 329
Herschel, William, 185, 234, 235, 244, 249, 274, 275, 280, 281, 282, 284,
288, 289, 290, 293, 295, 305, 309, 310, 318, 319, 327;
he "sweeps" the heavens, 280;
his discovery of Uranus, 281, 287;
his artificial Saturn, 281, 282;
his methods of work with his sister, described, 284;
he founded the science of Astronomy, 287
Hind, 300
Hipparchus, 7, 18, 20, 27, 28, and note, 30, 40, 66, 223, 253;
an explanation of his discovery of the precession of the equinoxes,
27, seq.
Hippocrates, 87
Homeric Cosmogony, 15, _seq._
Hooke, 139, 188, 192, 193, 196, 197, 308
Hopital, Marquis de l', 228
Horkey, Martin, 106
Horrebow, 244
Huxley, Prof., 149
Huyghens, 86, 166, 185
K
Kant, 267, 270
Kelvin, Lord, see Thomson, Sir W.
Kepler, John, 59, 60, 63, 64, 65, 66, 70, 72, 73, 75, 77, 79, 84, 93,
94, 95, 104, 106, 107, 110, 122, 137, 145, 153, 158, 164, 165, 166,
167, 192, 200, 208, 209, 210, 211, 212, 214, 218, 224, 227, 253, 256,
259, 260, 262, 288, 295, 296, 332, 338, 361, 389;
he replaced epicycles by an ellipse, 27;
he was a pupil of Tycho Brahe, 54;
he was a speculator more than an observer, 58;
his personal life, 58, _seq._;
his theories about the numbers and distances of the planets, 60, 62;
he was helped by Tycho, 63;
his main work, 65, _seq._;
he gave up circular motion, 69;
his _Mysterium Cosmographicon_, 105;
his Laws, 71, 74, 173, 174, 176, 179, 180, 206, _seq._
L
Lagrange, 193, 234, 255, 256, 257, 258, 263
Lagrange and Laplace, 258, 266, 395;
they laid the foundations of the planetary theory, 259
Laplace, 68, 193, 218, 234, 255, 261, 262, 267, 268, 269, 270, 272,
288, 301, 317, 384, 385, 390;
his nebular hypothesis, 267, 292;
his _Mecanique Celeste_, 323
Lassell, Mr., 283, 284
Leibnitz, 192, 197, 233
Le Monnier, 319
Leonardo, see Vinci, Leonardo da
Leverrier, 193, 327, 328, 329, 330, 352
Lippershey, Hans, 95
M
Maskelyne, 281
Maxwell, Clerk, 302, 303
Molyneux, 248, 249
Morton, Mr. E.J. C, his Life of Copernicus, 31
N
Newton, Prof. H.A., 347
Newton, Sir Isaac, 7, 30, 79, 138, 139, 144, 145, 149, 153, 157, 158,
165, 166, 167, 174, 176, 184, 187, 188, 189, 191, 192, 194, 196, 198,
199, 201, 213, 216, 219, 220, 221, 224, 226, 227, 228, 233, 242, 253,
255, 256, 274, 288, 317, 340, 378;
his _Principia_, 191, 192, 193, 194, 195, 196, 197, 207, 214, 216, 218,
228, 233, 242, 253;
his early life, 161, _seq._;
his first experiments, 163;
his work at Cambridge, 164;
his Laws, 168;
his application of the Laws of Gravity to Astronomy, 177, 178, 179, 185,
190;
his reticence, 178;
his discoveries in Optics, 181, _seq._;
his work summarised, 186;
his _Optics_, 189;
anecdotes of him, 191;
his appearance in a Court of Justice, 195;
some of his manuscripts very recently discovered, 217;
his theories of the Equinoxes and tides, 223, _seq._, 225, 363, _seq._
O
Olbers, 299, 300
P
Peters, Prof., 300, 316
Piazzi, 298, 299, 308, 313
Picard, 190, 242, 244, 247
Pioneers, genuine, 7
Planets and days of the week, 18
Poynting, 332
Printing, 9
Ptolemy, 18, 20, 27, 38, 153, 155, 166, 214;
his system of the Heavens simplified by Copernicus, 11, 30;
his system described, 19, _seq._;
his system taught, 34;
his harmonies, 74
Pythagoras, 19, 20, 34
Q
Quadrant, an early, 42, 43
R
Rheiter, 107
Ricci, Ostillio, 86, 87
Roberts, Isaac, 268
Roemer, 239, 240, 242, 244, 249, 251, 308
Rosse, Lord, his telescope, 186, 268
Rudolphine tables, 65
S
Scheiner, 107
Sizzi, Francesca, an orthodox astronomer, 106
Snell, Willebrod, and the law of refraction, 65
Solar system, its fate, 265
Stars, a list of, 307
Struve, 308, 310, 311, 313
Stuart, Prof., quoted, 52
T
Tatius, 296
Telescopes, early, 96
Thales, 7, 140, 317
Thomson, Sir William, 367, 372, 373, 378, 394
Tide-gauge, described, 373, _seq._
Tides, 354, _seq._
Time, is not exactly uniform, 384
Torricelli, 133, 168
Tycho, see Brahe, Tycho
V
Vinci, Leonardo da, 9, 100, 144, 184
Viviani, 133, 168
Voltaire, 181
W
Watson, Prof., 300
Whewell, 227
Wren, Sir Christopher, 188, 192, 193, 197
Z
Zach, Von, 296, 299
Zone of Asteroids, 300, _seq._
THE END.
RICHARD CLAY AND SONS, LIMITED, LONDON AND BUNGAY.