THE SIDEREAL UNIVERSE. 737 



of a perfect swarm of suns, for each of their imperceptible 

 stars represents a sun. 



The stars which form the nebulae are so massed together 

 that they cannot be counted with exactness. Astrono- 



324. The Dumb-bell Nebula, Constellation of the Fox (Vulpeada). 



mers have only been able to calculate approximately the 

 number in several of those which present a globular form. 

 Arago asserts that there are as many as 20,000 in some 

 of those celestial lights which ai'e in appearance not more 

 than one-tenth of the magnitude of the moon's disk. 



These bodies are scattered irregularly enough over the 

 celestial vault. Large spaces seem entirely Avithout them, 

 whilst in other regions they are dispersed like numerous 

 archipelagoes, and the observer can, for instance, particu- 

 larly near the Virgin, see more than 300 traverse the field 

 of the telescope within an hour. 



