316 M. Aiago on Nebulce. 



Of the Light of true Nehulce, — Starry nebulae have been re- 

 garded for a long time as true nebulae. We must not, there- 

 fore, expect to discover dissimilarities of a very decided 

 character between the lidits of these two natures of bodies. 

 Nebulae, composed of a diffused, continuous, phosphorescent 

 matter, have, however, quite a peculiar and indefinable aspect, 

 with which the most ancient observers who had an opportu- 

 nity of examining the heavens with good glasses, appear to 

 have been particularly struck. 



Halley, for example, did not hesitate to regard the light 

 of the nebulae of Orion and Andromeda, as depending on quite 

 a particular cause. " In reality," he says,' " these spots are 

 nothing else but the light coming from an extraordinary great 

 space in the ether, through which a lucid medium is diffused 

 that shines with its own proper lustre."* >! 



Derham is not less explicit ; the light of nebulae, according 

 to him, could not be that of a congregation of stars. He even 

 proceeds to ask if, as many philosophers formerly believed, 

 there may not exist beyond the sphere of the remotest stars, 

 a region entirely luminous, an empyrean heaven, and if these 

 nebulae be not this shining region seen through an opening, 

 a chasm, of the sphere (probably crystalline) of the primum 

 mobile, 



Voltaire mentions Derham's opinion in one of his ingenious 

 romances. 



'* Micromegas," he says, '* traversed the Milky Way in a 

 short time ; and I am obliged to confess that he never saw, 

 across the stars with which it is sprinkled, the beautiful em- 

 pyrean heaven which the illustrious vicar Derham boasts of 

 having seen at the end of his glass. Not that I allege that 

 M. Derham saw wrong ; God forbid I but Micromegas was 



• We find in the Memoir frorn which I extract this passage, a remark, 

 which is the more singular, as it was made by a man who almost openly 

 professed infidelity. " This," wrote the friend of Newton, " seems fully to 

 reconcile that difficulty which some have moved against the description 

 Moses gives of the creation, alleging that light could not be created without 

 the sun. But in the instances of Nebulae the contrary is manifest ; for some 

 of these bright spots discover no sign of a star in the middle of them." 



