776 



INDEX. 



medium, 523; solar parallax, 

 562. 



Energy, unit of, 322 ; conservation 

 of, 465; reconcentration of, 751. 



English language, words in, 175. 



Eozoon canadense, 412, 668. 



Equality, sign of, 14 ; axiom, 163; 

 four meanings of, 479. 



Equations, 46, 53, 160 ; solution of, 

 123. 



Equilibrium, unstable, 276, 654. 



Equisetacese, 721. 



Equivalence of propositions, 115, 

 120, 132; remarkable case of, 

 529, 657. 



Eratosthenes, sieve of, 82, 123, 

 139 ; measurement of degree, 

 293. 



Error, function, 330, 376, 381 ; 

 elimination of, 339, 353 ; per- 

 sonal, 347 ; law of, 374 ; origin 

 of law, 383 ; verification of law, 

 383 ; probable, 386 ; mean, 387 ; 

 constant, 396 ; variation of small 

 errors, 479. 



Ether, luminiferous, 512, 514, 605. 



Euclid, axioms, 51, 163; indirect 

 proof, 84 ; 10th book, 117th 

 proposition, 275 ; on analogy, 

 631. 



Euler, on certainty of inference, 

 238 ; corpuscular theory, 435 ; 

 gravity, 463 ; on ether, 514. 



Everett, Professor, unit of angle, 

 306 ; metric system, 328. 



Evolution, theory of, 761. 



Exact science, 456. 



Exceptions, 132, 644, 728 ; classifi- 

 cation of, 645 ; imaginary, 647 ; 

 apparent, 649 ; singular, 652 ; 

 divergent, 655 ; accidental, 658 ; 

 novel, 661 ; limiting, 663 ; real, 

 666 ; unclassed, 668. 



Excluded middle, law of, 6. 



Exclusive alternatives, 68. 



Exhaustive investigation, 418. 



Expansion, of bodies, 478 ; of 

 liquids, 488. 



Experiment, 400, 416 ; in proba- 

 bility, 208 ; test or blind, 433 ; 

 negative results of, 434; limits 

 of, 437 ; collective, 445 ; sim- 

 plification of, 422 ; failure in 

 simplification, 424. 



Experimentalist, character of, 574, 



Experimentum crucis, 518, 667. 



Explanation, 532. 



Extent of meaning, 26 ; of terms, 



48. 

 Extrapolation, 495. 



FACTORIALS, 179. 



Facts, importance of false, 414 , 

 conformity with, 516. 



Fallacies, 62 ; analysed by indirect 

 method, 102 ; of observation, 40 8, 



Faraday, Michael, measurement of 

 gold-leaf, 296 ; on gravity, 342, 

 589 ; magnetism of gases, 352 ; 

 vibrating plate, 419 ; electric 

 poles, 421 ; circularly polarised 

 light, 424, 588, 630 ; freezing 

 mixtures, 427 ; magnetic experi- 

 ments, 431, 434 ; lines of mag- 

 netic force, 446, 580 ; errors of 

 experiment, 465 ; electrolysis, 

 502 ; velocity of light, 520 ; 'pre- 

 diction, 543 ; relations of phy- 

 sical forces, 547 ; character of, 

 578, 587 ; ray vibrations, 579 ; 

 mathematical power, 580 ; philo- 

 sophic reservation of opinion, 

 592 ; use of heavy glass, 609 ; 

 electricity, 612 ; radiant matter, 

 642 ; hydrogen, 691. 



Fatality, belief in, 264. 



Ferio, 56. 



Figurate numbers, 183, 186. 



Figure of earth, 459, 565. 



Fizeau, use of Newton's rings, 297, 

 82 ; fixity of properties, 313 ; 

 velocity of light, 441, 561. 



Flamsteed, use of wells, 294 ; 

 standard stars, 301 ; parallax of 

 pole-star, 338 ; selection of obser- 

 vations, 358 ; astronomical in- 

 struments, 391 ; solar eclipses, 

 486. 



Fluorescence, 664. 



Fonteuelle on the senses, 405 



Forbes, J. D., 248 



Force, unit of, 322, 326 ; ema- 

 nating, 464 ; representation of, 

 633. 



Formulae, empirical, 487 ; rational, 

 489. 



Fortia, Trattt des Progressions, 1 83. 



Fortuitous coincidences, 261. 



Fossils, 661. 



Foster, G. C,, on classification, 691. 



Foucault, rotating mirror, 299 ; pen- 



