CHAPTER X. 



NOTES ON NEBULJE. 



I 4M attempting in these pages to give a conception of 

 the -varied nature of the objects which the skies offer to 

 our contemplation. In the moon we have a body of the 

 most solid description, evidently cold and hard. We 

 then saw that Saturn was entirely destitute of those rigid 

 features which gave the moon its beauty. The charms of 

 Saturn lie in quite another direction. Then we passed 

 from these sun-illuminated bodies to a group of suns 

 themselves in the glorious star cluster. Now we look 

 to an entirely different class of objects. 



The telescope, ever an ally in the study of the heavens, 

 is in this part of the science absolutely indispensable. In 

 other branches of astronomy we can learn something with- 

 out its aid. Indeed, many great astronomical discoveries 

 were made long before the telescope was invented. But 

 ere this memorable event in the history of science it was 

 impossible for us to know anything of the existence of the 

 nebulae. It is indeed true that there is one of these ob- 

 jects which can be just detected by the naked eye. It 



