300 COSMOS. 



which could not be seen with telescopes of low powers." 

 There are reasons for regarding the assertion of an alteration 

 of figure as a delusion ; not entirely so the existence of stars 

 in the nebula in Andromeda since the remarkable observations 

 of George Bond. Cassini, moreover, conjectured, on theoreti- 

 cal grounds, the possibility of such a resolution of the nebula; 

 since, in direct opposition to Halley and Derham, he consi- 

 dered all nebulous spots to be very remote stellar swarms. 15 

 The faint mild effulgence in Andromeda was indeed according 

 to his opinion analogous to the zodiacal light, which he also 

 conjectured to be composed of a crowd of densely thronged 

 small planetary bodies. 16 Lacaille's residence in the southern 

 hemisphere (at the Cape of Good Hope, and in the Isle of 

 France and Bourbon, between 1750-1752), so considerably 

 increased the number of known nebulous spots, that Struve 

 has justly remarked, that from the observations of this tra- 

 veller more was known at that time of the nebulous bodies 

 of the southern hemisphere, than of those which were visi- 

 ble in Europe. Lacaille, moreover, successfully attempted to 

 divide nebulre into classes according to their apparent con- 



15 "Dans les deux nebuleuses d'Andromede et d' Orion, 

 j'ai vu des etoiles qu'on n'apercoit pas avec des lunettes 

 communes. Nous ne savons pas si Ton ne pourrait pas avoir 

 des lunettes assez grandes pour que toute la nebulosite put se 

 resoudre en de plus petites etoiles, comme il arrive a celle du 

 Cancer et du Sagittaire." " I have seen stars in the nebulse 

 of Andromeda and Orion," says Dominique Cassini, "which 

 cannot be recognized by ordinary instruments. We are igno- 

 rant whether telescopes may not be constructed of sufficient 

 power to resolve the whole nebula into smaller stars, as has 

 been done in the case of the nebula3 in Cancer and Sagitta- 

 rius." Delambre, Hist, de VAstr. moderne, torn. ii. pp. 700 

 and 744. 



16 Cosmos, vol. i. p. 130, note. 



