INDEX. 



A. 



ABERRATION of light, 35. Note 98. 



Absorption of solar light by the atmo- 

 sphere, 176. 



of light by coloured media, 180. 



not inconsistent with the undula- 



tory theory, 197. 



Acceleration in the mean motion of the 

 moon, 42. 



of Encke's comet, 394. 



of Biela's comet, 395. 



Accidental colours, 184. 



Achromatic telescope, 184. Note 192. 



Action and reaction, 6. Note 19. 



of light on the retina, 199. 



Adams, Mr., the discoverer of the planet 

 Neptune, 71. 



Adhesion of glass plates, 119. 



Affinity, chemical, 122. 



Air, atmospheric, analysis of, 131. 



Airy, Professor, his determination of 

 the inequality of the earth and Ve- 

 nus, 30. His experiments on the 

 motion of polarized light through 

 quartz, 216. 



Algae, or sea-weeds, their distribution, 

 305. 



Algol, a variable star, 423. 



Alhazen the Saracen observed the ef- 

 fects of refraction, 173. 



Altitude, the height of a celestial body 

 above the horizon, 172. 



Ampere, M., his theory of electro-dyna- 

 mics, 361. 



Analogy between a stretched cord and 

 the interference of light, 217. 



between the different rays of the 



solar spectrum, 253. 



between light, heat, and sound, 



264. 



Analytical formula, 119. Note 158. 



Analyzing plate, a piece of glass, or a 

 slice of a crystal, used for examining 

 the properties of polarized light, 2C9. 



Analysis, 2. Note 3. 



Ancient chronology, 98. 



Angle of position of a double star, 417- 



Angular motion of the earth, 103. Note 

 152. 



velocity, 74, 103. Notes 89, 138, 



152. 



- motions of the first three of Jupi- 

 ter's satellites, 33. Note 89. 



Animal electricity, 340. 



Animals, distribution of, 307. 



Annual equation, 41. 



Anomaly, mean, 43. Note 106. 



Antarctic Ocean the principal source 

 of our tides, 107. 



Aphelion, 18. Note 65. 



Apsides, 11, 18. Notes 49, 66. 



, motion of, 19. Note 67- 



Arabian science, 29, 44, 101. 



Arago, M., his experiments on polarized 

 light, 217, 221. His observations on 

 the temperature of the earth and the 

 air above it, 296. His discovery of 

 electricity from rotation, 371. His 

 Treatise on Comets, 396. On the 

 probability of the earth being struck 

 by a comet, ib. He proves that co- 

 mets shine by reflected light, 409. 

 His estimate of the number of comets, 

 411. 



Arc of the meridian, 53. Notes, 124, 

 125. 



Arcs a measure of time, 23. Note 76. 



Areas proportional to the time, 10. 

 Note 41. 



Argelander, M., on the motion of the 

 sun, 432. 



