INDEX. 



Syllogism, 140 ; moods of, 55, 84, 

 85, 88, 105, 141; numerically 

 definite, 168. 



Symbols, use of, 13, 31, 32; of 

 quantity, 33. 



Synthesis, 122 ; of terms. 30. 



TABLE-TTJRNING, 671. 



Tacit knowledge, 43. 



Tacquet on combinations, 179. 



Tait, P. G., 375 ; theory of comets, 

 571. 



Talbot on the spectrum, 429. 



Tartaglia on projectiles, 466. 



Tastes, classification of, 732. 



Tautologous propositions, 119. 



Teeth, use in classification, 710. 



Temperature, variations of, 453. 



Tension of aqueous vapour, 500. 



Terms, 24 ; abstract, 27 ; sub- 

 stantial, 28 ; collective, 29 ; syn- 

 thesis of, 30 ; negative, 45. 



Terrot, Bishop, on probability, 212. 



Test experiments, 347, 433. 



Tetractys, 95. 



Thales, predicted eclipse, 537. 



Theory, results of, 534 ; facts known 

 by, 547 ; quantitative, 551 ; of 

 exchanges, 571 ; freedom of form- 

 ing, 577 ; of evolution, 761. 



Thermometer, differential, 345 ; 

 reading of, 390 ; change of zero, 

 390. 



Thermopile, 3UO. 



Thomas, arithmetical machine, 107. 



Thomson, Archbishop, 50, 61. 



Thomson, James, prediction by, 

 542 ; on gaseous state, 654. 



Thomson, Sir "W., lighthouse sig- 

 nals, '194 ; size of atoms, 195 ; 

 tides, 450 ; capillary attraction, 

 614 ; magnetism, 665 ; dissipa- 

 tion of energy, 744. 



Thomson and Tait, chronometry, 

 311 ; standards of length, 315 ; 

 the crowbar, 460 ; polarised light, 

 653. , 



Thomson, Sir Wyville, 412. 



Thunder-cloud, 612. 



Tides, 366, 450, 476, 541 ; velocity 

 of, 298 ; gauge, 368 ; atmospheric, 

 367, 553. 



Time, 220 ; definition of, 307. 



Todhunter, Isaac, History of the 

 Theory of Probability, 256, 375, 

 395 : on insoluble problems, 757. 



Tooke, Home, on cause, 226. 



Torricelli. cycloid, 235 ; his theo- 

 rem, 60.5 ; on barometer, 666. 



Torsion balance, 272, 287. 



Transit of Venus, 294, 348, 562. 



Transit-circle, 355. 



Tree of Porphyry, 702 ; of Eamus, 

 703. 



Triangle, arithmetical, 93, 182. 



Triangular numbers, 185. 



Trigonometrical survey, 301 ; cal- 

 culations of, 756. 



Trisection of angles, 414. 



Tuning-fork, 541. 



Tycho Brahe, 271 ; on star discs, 

 277 ; obliquity of earth's axis, 

 289 ; circumpolar stars, 366 ; 

 Sirius, 390. 



Tyndall, Professor, on natural con- 

 stants, 328 ; magnetism of gases, 

 352 ; precaution in experiments, 

 431 ; use of imagination, 509 ; 

 on Faraday, 547 ; magnetism, 

 549, 607 ; scope for discovery, 

 753. 



s, of logical conditions, 140, 

 L~44 ; of statements, 145 ; classi- 

 fication by, 722. 



UEBERWEG'S logic, 6. 



Ultimate statements, 144. 



Undistributed, attribute, 40 ; middle 

 term, 64, 103. 



Undulations, of light, 558 ; analogy 

 in theory of, 635. 



Undulatory theory, 468, 520, 538, 

 540 ; inconceivability of, 5 1 0. 



Unique objects, 728. 



Unit, definition of, 157; groups, 

 167 ; of measurement, 305 ; 

 arcual, 306 ; of time, 307 ; 

 space, 312 ; density, 316 ; mass, 

 317 ; subsidiary, 320 ; derived, 

 32 1 ; provisional, 323 ; of heat, 

 325 ; magnetical and electrical 

 units, 326, 327. 



Unity, law of, 72. 



Universe, logical, 43 ; infiniteness 

 of, 738 ; heat-history of, 744, 

 749 ; possible states of, 749. 



Uranus, anomalies of, 660. 



VACUUM, Nature's abhorrence of, 



513. 



Vapour densities, 648. 

 Variable, variant, 440, 441, 483. 

 3 E 



