ne 



INDEX. 



Cosiiiical vnpor, question as to condensa- 

 tion of; 37 ; Tvcho Brahe's and Sir Will- 

 iam llerschers theories, 154. 



•' Cosmos," a pseudo-Aiistotelian work, 

 16. 



Crystal vault of heaven, date of the desig- 

 nation, 123 ; its signification according 

 to Erapedocles, 1'^ ; the idea favored 

 by the Fathers of the Church, 125. 



Cyanometer, Arago's, 97. 



Dark cosmical bodies, question of, 164, 

 187. 



Dolambre on the velocity of light, 82. 



Descartes, his cosmical views, 19, 20 ; sup- 

 presses his work from detbrence to tlie 

 Inquisition, 20. 



Dioptric tubes, the precursors of the tele- 

 scope, 43. 



Direct and reflected light, 45. 



Distribution of the fixed stars, according 

 to right ascension, 140. 



Dorpat Table (Struve's) of multiple stars, 

 205, 



Double stars, the name too indiscrimin- 

 ately applied, 199, 200 ; distribution into 

 optical and physical. 200 ; pointed out 

 by Galileo as useful in determining the 

 parallax, 200 ; vast increase in their ob- 

 served number, 201, 205 ; those earliest 

 described, 201 ; number in wiiich a 

 change of position has been proved, 

 206 ; greater number of double stars in 

 the northern than in the southern hem- 

 isphere, 207 ; occurrence of contrasted 

 colors, 207 ; calculation of theix orbits, 

 211 ; table of the elements, 213. 



Earth-animal, Kepler and Fludd's fancies 

 regarding the, 19. 



Edda-Songs, allusion to, 8. 



Egypt, zodiacal constellationa of, their 

 date, 121. 



Egyptian calendar, period of the complete 

 arrangement of the, 133. 



Ehrenberg on the incalculable number 

 of animal organisms, 30. 



Electrical light, velocity of transmission 

 of, 86. 



Electricity, transmission o^ through the 

 earth, 88. 



Elements, Indian origin of the hypothesis 

 of four or five, 11. 



Emanations Irom the head of some com- 

 ets, 39. 



Encke, his accurate calculation of the 

 equivalent of an equatorial degree, 81 ; 

 on the star-maps of the BerUn Academy, 

 116 ; an early calculator of the orbits 

 of double stars, 2i 1 ; his theory of their 

 motion, 212. 



Encke's comet, cocsiderations on space, 

 derived from periods of revolution of, 

 27 ; a resisting medium proved from 

 observation on, 39, 



Ether, different meanings of, in the East 

 and the West, 31, 32. 



Etlier (Akd'sa, in Sanscrit), ore of the In- 

 dian five elements, 31 



r.lher, the, fiery, 35. 



Euler's ccmparative estmiate of the light 

 of the sun and moon^ 95. 



Fixed stars, the term erroneous, 27, 123 ; 

 scintillation of the, 73 ; variations in iU 

 intensity, 76 ; our sun one of the fainter 

 fixed stars, 95; photometric arrango 

 ment of, 99; their number, 105; num- 

 ber •sisible at Berlin with the naked eye, 

 107; at Alexandria, 107; Struve and 

 Herschel's estimates, 116; grouping of 

 the, 117 ; distribution of the, 140; prop- 

 er motion of the, 182; parallax, 188; 

 number of, in which proper motion has 

 been discovered, greater than of thoso 

 in which change of position has been 

 observed, 206, 207. 



Fizeau, M., his experiments on the veloc- 

 ity of light, 80, 83. 



Fonnula tor computing variation nf light 

 of a star, by Argelander, 168, 169. 



Galactic circle, average number of stars 

 in, and beyond the, 139. 



Galileo indicates the means of discover- 

 ing the parallax, 188. 



Galle, Dr., on Jupiter's satellites, 50 ; on 

 the photometric arrangement of the 

 fixed stars, 99. 



Garnet star, the, a star in Cepheus, so 

 called by William Herschel, 166. 



Gascoigne applies micrometer threads to 

 the telescope, 42. 



Gauging the heavens, by Sir William Her- 

 schel, 138, 139 ; length of time neces- 

 sary to complete the process, 139. 



Gauss, on the point of translation in space 

 of the whole solar system, 196. 



Gilliss, Lieutenant, on the change of color 

 of the star rj Argiis, 135. 



Gravitation, not an essential property of 

 bodies, but the result of some higher 

 and still unknown power, 22, 23. 



Greek sphere, date of the, 119, 121. 



Green and blue suns, 208. 



Groups of fixed stars, recognized even 

 by the rudest nations, 117 ; usually the 

 same groups, as the Pleiades, the Great 

 Bear, the Southern Cross, &c., 117, 118. 



Halley asserted the motion of Sirius and 

 other fixed stars, 26, 27. 



Hasscnfratz, his description of the raya 

 of stars as caustics on the crj'stalliae 

 lens, 52, 127. 



Heat, radiating, 35. 



Hepidannus, monk of Saint Gall, a new 

 star recorded by, 157, 162. 



Herschel, Sir William, on the vilifying 

 action of the sun's rays, 34 ; his estimate 

 of the number of the fixed stars, 116, 

 117; his "gauging the heavens," and its 

 result, 138, 139. 



Herschel, Sir John, on the transmission 

 of light, 30; on the influence of the sun's 

 rays, 34 ; compares the sun to a per- 

 petual northern light, 34 ; on the at- 

 mosphere, 37 ; on the blackness of the 

 ground of the heavens, 39 ; on stan 

 seen in daylight, 57 ; on photousctry. 



