370 



His analysis of sound, 247, 

 Hypothesis of light, 250. 

 Examination of a soap-bub- 

 ble, 252. His hypothesis 

 of fits of easy transmission 

 and reflection, 253. His 

 combination of mathema- 

 tical skill with physical re- 

 search, 271. His Principia, 

 272. His successors ; his 

 geometry, 273. 



Nomenclature, importance of, 

 to science, 136. More a 

 consequence than a cause 

 of extended knowledge, 

 138. Prejudicial to mi- 

 neralogy, 139. 



Norman, Robert, his disco- 

 very of the dip of the 

 needle, 327. 



Numerical precision, necessity 

 of, in science, 122. 



Objects, and their mutual 

 actions, subjects of con- 

 templation, 118. 



Observation, a means of ac- 

 quiring experience, 76. 

 Passive and active, 77. Re- 

 corded observation, 120. 

 Necessity of, to acquire 

 precise physical data, 215. 

 Illustrated by the barome- 

 ter, 216. 



Oersted, his discoveries in 

 electricity and magnetism, 

 132. Of electro-magnet- 

 ism, 34O. 



Opacity, 189. 



Otto von Guerickeot Magde- 

 burgh, his invention of the 

 air-pump, 230. 



Paracelsus, power of his 

 remedies ; his use 



I of mercury, opium, and 

 tartar, 112. 



Pascal, his crucial instances 

 proving the weight of air, 

 229. 



Pendulum, 1 26. 



Phenomena, analysis of, il- 

 lustrated by musical sounds, 

 the sensation of taste, 85. 

 The ultimate and inward 

 process of nature in the pro- 

 duction of, 86. Analysis 

 of complex phenomena, 88. 

 Ultimate phenomena, 90. 

 How the analysis of, is use- 

 ful, 97. A transient phe- 

 nomenon, how to judge of, 

 1 22. Method of explaining 

 one when it presents itself, 

 148. How to discover the 

 cause of one, 150. Two, or 

 many, theories, maintained 

 as the origin of, in, physics, 

 195. Cosmical phenomena, 

 265. 



Philosophy, natural, unfound- 

 ed objections to the study 

 of, 7. Advantages derivable 

 from the study of, 10. Plea- 

 sure and happiness, the con- 

 sequences of the study of, 1 5. 



Phlogistic doctrines of Bec- 

 cher and Stahl, 300. 



Physical data, necessity of, 

 209. Great importance of, 

 211. Illustrated by the 

 erection of observatories, 

 21 3. Necessity of an exact 

 knowledge of, 214. More 

 precise than the observations 

 by which we acquire them. 

 215. 



Physics, axioms of ; analysis 

 of, 102. 



Planets, circumjovial, 1 86. . 



Platina, discovery of, 808. 



