INDEX. 



479 



Sorites, i. 72. 



Sounds, ii. 97, 271 ; velocity of, i. 412 ; 

 ii. 213; interference of, 176; classi- 

 fication of, 423. 

 Species, ii. 376; mfima, 380; natural, 



414. 



Specific heat of air, ii. 197. 

 Spectrum, i. 329, 348; ii. 9, 97, 229, 



251 ; Thomas Melvill on, 38. 

 Spencer, Herbert, laws of thought, i. 

 9; sign of equality, 1 8 ; rhythmical 

 motion, ii. 61 ; abstraction and gene- 

 ralization, 390 ; theories of, 405 ; 

 quantification of predicate, 387. 

 Spontaneous generation, ii. 43. 

 Standards, i. 365. 



Stars, motion of, i. 325, 348 ; ii. 93. 

 95, 215 ; variable, i. 326 ; ii.64, 358; 

 discs, i. 464 ; coloured, ii. 358 ; heat 

 of, i. 430 ; conflict with, 443. 

 Stevinus, ii. 276. 

 Stewart, Balfour, sun-spots, ii. 67 ; 



ethereal friction, 213. 

 Stifels, i. 206. 



Stokes, on resistance, ii. 96; fluor- 

 escence, 332. 



Stone, E. J., radiant heat of stars, i. 

 430; temperature periods, ii. 67; 

 transit of Venus, 204. 

 Strutt, J. W., graphical method, ii. 



119. 



Substantial terms, i. 34. 

 Substitution of similars, i. 21, 25; 11. 



345 ; of weights, i. 23, 399. 

 Sui generis, ii. 286, 418. 

 Sulphur, ii. 341. 

 Summum genus, i. 108; ii. 379. 

 Sun, distance, ii. 204. 

 Swan, W., sodium light, ii. 39. 

 Syllogism, Barbara, i. 66, 103, 121 

 Celarent, 67 ; Darii, Ferio, 67, 68 

 Darapti, 71 ; Camestres, Cesare, 99 

 Baroko, Bocardo, 100; disjunctive 

 92. 



Symbols, logical, i. 39. 

 Synthesis, of terms, i: 36 ; of laws, 140 

 Syren, i. 12, 348; ii. 28. 



T. 



Table-turning, ii. 342. 



Tastes, ii. 423. 



Tautologous propositions, i. 138. 



Teeth, as criteria of classification, i 



395- 



Temperature, ii. 68. 



Terms, i. 29 ; substantial, 24 ; collec 

 tive, 35 ; synthesis of, 36 ; abstrac 

 38 ; logical and numerical, 1 80. 



Test experiments,!. 402. 



Tetractys, i. no. 



Thales, ii. 171. 



Theory, results of, ii. 1 68 ; facts known 

 by, 185 ; quantitative, 189, 192 ; dis- 

 cordance of, 198. 



Thermometer, differential, i. 400 ; read- 

 ing of, 404; change of zero, 455- 



'hermopile, i. 348. 



"homson, James, ii. 178. 



Thomson, Sir W., size of atoms, i. 222 ; 

 tides, ii. 64; thermal phenomena, 

 180, 197 ; capillary attraction, 267 ; 

 magnetism, 333; heat-history of uni- 

 verse, 438. 



Thomson and Tait, chronometry, i. 364 ; 

 problem of bars, ii. 77; polarised 

 light, 318. 



Dide-guage, i. 427. 



Tides, ii. 64, 66, 98, 178, 195; atmo- 

 spheric, i. 425, 426 ; ii. 192. 



Time, measurement of, i. 359 ; equal 

 times, 362. 



Todhunter, on Michell's speculations, i. 

 286 ; his History, 460. 



Torricelli, ii. 336 ; theorem of, 67, 256. 



Torsion-balance, i. 354 ; ii. 7^- 



Transit, instrument, i. 411; of Venus, 



i. 343> 399 5 202 - 



Tree of Porphyry, ii. 381. 



Triangle, arithmetical, i. 108, 439, 444; 

 offerees, ii. 292. 



Triangular numbers, i. 209. 



Trigonometrical survey, i. 351 ; ii. 453- 



Tycho Brahe, on star discs, i. 314, 321 ; 

 obliquity of earth's axis, 337 ; cir- 

 cumpolar stars, 425 ; Sirius, 454. 



Tynda'.l, natural constants, i. 380 ; 

 precautions in experiment, ii. 41 ; 

 singing flames, 109 ; use of hypo- 

 thesis, 134; magnetism, 188 ; scope 

 for discovery, 499. 



Types, classification by, ii. 409, 411. 



U. 



Undistributed middle, i. 77. 

 Undulations, ii. 176, 293. 423. 

 Undulatory theory, ii. 150,^174, 3 T 5, 



337- 



Uniformity of nature, 11. 440. 



Unit, definition of, i. 1 76 ; of time, 359 ; 

 of space, 365; of density, 371; of 

 mass, 372 ; subsidiary, 374; derived, 

 375 ; provisionally independent, 377. 



Unity, law of, i. 86, 176, 182. 



V. 



Vapour-densities, ii. 1 86; anomalous, 



339- 



Variable, variant, n. 51, no. 

 Variation, instance of, i. 324 ; method 



of, ii. 50 ; periodic, 61 ; combined 



