INDEX. 



621 



DIF 



Difficulties in a research, rule for 

 overcoming them, 380 



Difficulty of estimating import- 

 ance of scientific truths, 189 



of explaining results, 449 



of selecting a subject of re- 

 search, 372 



Diffusion of liquids, Sir W. Thom- 

 son's experiments on the, 558 



Diffraction of light, discovery of 

 the, 565 



Discoverers, ability of women as 

 scientific, 282-284 



books on the lives of, 262 



contrasted with barren reason- 

 ers, 251-252 



early circumstances of, 263-264 

 Discoveries, ' accidental,' 223 



in the arts, 395 



dependency of upon previous 

 ones, 170, 183, 223 



examples of false, 135-137 



rarity of great, 195 



made by women, 282 



missed, instances of, 321, 452, 

 595 



prediction of, 227 



predicted, examples of, 204, 

 227, 229, 233, 524 



relative importance of dif- 

 ferent, 189 



unexpected, 223, 235 



yet to be made, 7, 22, 26-28, 

 394, 469, 563 



Discovery aided by analogy, 327 

 hypotheses, 363-367 



and invention, difference be- 

 tween, 3 



a condition of invention, 471 



by analysis and synthesis, 217, 

 524-525 



applying electricity to bo- 

 dies, 553-555 



heat to substances, 551- 



553 



asking questions and testing 



them, 513 



by assuming the certainty of 

 all the great principles of sci- 

 ence, 519-520 



D1S 



Discovery by assuming the ex- 

 istence of complete homologous 

 series, 524 



existence of converse 



principles of action, 522-523 



that certain general 

 statements which are true of 

 one force or substance are true 

 to some extent of others, 522 



the combined action of 

 many observers, 575 



comparing facts and col- 

 lecting similar ones, 580-581 



collections of facts with 



each other, 581-582 



the orders of collections 



of facts, 583 



comparison of facts with 

 hypotheses, 579-580 



deductive process, 460 



employing new or improved 



means of observation, 572-574 

 examining the ashes of rare 



plants and animals, 507 

 common but neglected 



substances, 501-502 

 the effects of contact of 



substances, 555-557 



of forces on sub- 

 stances, 550-555 



of extreme degrees of 



force, 559-560 

 extreme or conspicuous 



instances, 500 



influence of time upon 

 phenomena, 557-559 



neglected truths and hy- 

 potheses, 487 



peculiar minerals, 503-505 



or unexpected truths, 



487 



rare substances, 504-505 



residual phenomena, 201- 



202 



residues of manufactures, 



505-507 



extending the researches of 



others, 544 



neglected parts of 

 science, 466-469 



