778 



INDEX. 



of, 349 ; experiments on, 444 ; 

 mechanical equivalent of, 568. 



Heavy glass, 588, 609. 



Helmholtz, on microscopy, 406 ; 

 undulations, 414 ; sound, 476. 



Hemihedral crystals, 649. 



Herschel, Sir John, on rotation of 

 plane of polarisation of light, 129, 

 (530 ; quartz crystals, 246 ; nu- 

 merical precision, 273 ; photo- 

 metry, 273 ; light of stars, 302 ; 

 actiuometer, 337 ; mean and 

 average, 363 ; eclipses of Jupiter's 

 satellites, 372 ; law of error, 377 ; 

 error in observations, 392 ; on 

 observation, 400 ; moon's influ- 

 ence on clouds, 410 ; comets, 411 ; 

 spectrum analysis, 429 ; collective 

 instances, 447, principle of forced 

 vibrations, 451, 663 ; meteoro- 

 logical variations, 489 ; double 

 stars, 499, 685 ; direct action, 

 502 ; use of theory, 508 ; ether, 

 515 ; experimentum crucis, 519 ; 

 interference of light, 539 ; inter- 

 ference of sound, 540 ; density of 

 earth, 567 ; residual phenomena, 

 569 ; helicoidal dissymmetry, 

 630 ; fluorescence, 664. 



Hindenburg, on combinatorial 

 analysis, 176. 



Hipparchus, used method of repeti- 

 tion,289 ; longitudes of stars, 294. 



Hippocrates, area of lunule, 480. 



History, science of, 760. 



Hobbes, Thomas, definition of cause, 

 224 ; definition of time, 307 ; on 

 hypothesis, 510. 



Hofmann, unit called crith, 321 ; 

 on prediction, 544 ; on anomalies, 

 670. 



Homogeneity, law of, 159, 327. 



Hooke, on gravitation, 436, 581 ; 

 philosophical method, 507 ; on 

 strange things, 671. 



Hopkinson, John, 194 ; method of 

 interpolation, 497. 



Horrocks, use of mean, 358 ; use 

 of hypothesis, 507. 



Hume on perception, 34. 



Hutton, density of earth, 566. 



Huxley, Professor Thomas, 764; 

 on hypothesis, 509; classification, 

 676 ; mammalia, 682 ; palaeon- 

 tology, 682. 



Huyghens, theory of pendulum, 302 ; 



pendulum standard, 315; cycloiclal 

 pendulum, 341 ; differential me- 

 thod, 344; distant stars, 405 ; use 

 of hypothesis, 508 ; philosophical 

 method of, 585 ; on analogy, 

 639. 



Hybrids, 727. 



Hydrogen, expansion of, 471 ; re- 

 fractive power, 527 ; metallic 

 nature of, 691. 



Hygrometry, 563. 



Hypotheses, use of, 265, 504 ; sub- 

 stitution of simple hypotheses, 

 458 ; working hypotheses, 509 ; 

 requisites of, 510; descriptive, 

 622, 686 ; representative, 524 ; 

 probability of, 559. 



IDENTICAL propositions, 119. 

 Identities, simple, 37 ; partial, 40 ; 



limited, 42; simple and partial, 



111 ; inference from, 51, 55. 

 Identity, law of, 5, 6, 74 ; expres- 



sion of, 14 ; propagating power, 



20 ; reciprocal, 46. 

 Illicit process, of major term, 65, 



103 ; of minor term, 65. 

 Immediate inference, 50, 61. 

 Imperfect induction, 146, 149. 

 Inclusion, relation of, 40. 

 Incommensurable quantities, 275. 

 Incompossible events, 205. 

 Independence of small effects, 475. 

 Independent events, 204. 

 Indestructibility of matter, 465. 

 Indexes, classification by, 714; 



formation of, 717. 

 India-rubber, properties of, 545. 

 Indirect method of deduction, 49, 



81 ; illustrations of, 98 ; fallacies 



analysed by, 102 ; the test of 



equivalence, 115. 



Induction, 11, 121 ; symbolic state- 



ct, 

 perfect, 149 ; philosophy of, 218 ; 



ment of, 131 



; sym 

 : perfect, 



146 ; im- 



grounds of, 228 ; illustrations of, 

 229 ; quantitative, 483 ; problem 

 of two classes, 134 ; problem of 

 three classes, 137. 



Inductive truths, classes of, 219. 



Inequalities, reasoning by, 47, 163, 

 165-166, 



Inference, 9 ; general formula of, 

 17 ; immediate, 50 ; with two 

 simple identities, 51 ; from 

 simple and partial identity, 53 ; 



