INDEX. 



637 



OIL 



Oils, discovery of various essentia 

 539-540 



Olbers's discovery respecting the 

 asteroids, 236, 509-510 



* Olynthus calcareous sponge,' in- 

 ference respecting, 604 



Omnipresence of natural phe- 

 nomena, 22-23 



Optical discovery by Fresnel, 229 



phenomena, discovery of the 

 true causes of, 590 



Orbit of the August meteors, dis- 

 covery of a comet in the, 609-610 



November meteors, discovery 



of a comet in the, 610 



Order of dependence of the sci- 

 ences, 184-186 



of discovery, chronological, 183 



of learning, 71 



of making a research, 457 



of making experiments, 308- 

 312 



Organic compounds, discovery of 

 series of, 524 



development, hypothesis of, 

 604-605 



Originality, nature of scientific, 



360 



Original scientific research, artis- 

 tic nature of, 6 



difficulties of, 11,209-219 



how to conduct an, 377- 



381, 383, 385, 389, 391 



extent of 1, 10 



limits of, 2 



object of, 1 



Osmium and iridium, discovery of, 



505-506 

 Otto Guericke's discoveries, 553, 



567 

 invention of an air-pump, 



474 

 Oxidation, Lavoisier's discoveries 



respecting, 475, 511-512 

 Oxide of manganese, discovery of 



its chemical properties, 556, 557 

 Oxygen, discovery of, 501, 539- 



540, 552 

 of some of the properties of, 



542 



PER 



Oxygen, liquefaction of, discovery 

 of the, 560 



PACIFIC Ocean, discovery of 

 silver in the water of the, 

 558-559 



Pacquet's discovery of the func- 

 tion of the lacteal vessels, 571 



Paetz and Von Troostwik's dis- 

 covery of the electrolysis of 

 water, 481, 554 



Palladium, Chenevix's mistake re- 

 specting, 107 



discovery of, 505 

 Pallas, discovery of, 236 

 Papin's discovery respecting the 



temperature of water boiling in 



vacuo, 529 

 Partnership method of research, 



275 



Pascal's discoveries, 226, 525-526 

 Passivity of iron and other metals, 



discovery of, 535 

 ' Path of least resistance,' 165 

 Patience as an aid to research, 



241, 255 



of great discoverers, 253 

 Peculiar or unexplained truths, 



discovery by examining, 487 

 Peltier's discovery of electro-ther- 



mancy, 548 

 Pendulum applied to clocks, 474 



discovery of the principle of 

 the, 487 



Perception, investigation of by 

 means of experiments, 57-59 



of ideas, automatic nature of, 

 43 



Persecution of scientific men, 267 

 Perseverance as an aid to success 



in research, 241, 255 

 Persistency of cerebral impres- 

 sions, 65-66 



of phenomena, 65, 161-162 



' Personal equation,' investigation 

 of, 58-59 



qualifications for discovery, 241 

 Perthe's discovery of the great 



antiquity of man, 602 



