THE SIDEREAL UNIVERSE. 



729 



only magnified objects seven times, and yet with it he dis- 

 covered the sateUites of Jupiter. 



At present Sir J. Herschel explores the stars with in- 

 struments which multiply 6500 times. Lord Rosse fathoms 



322. The great Reflecting Telescope constructed by Lord Eosse. 

 Exploration of tlie Infinitely Great. 



the dejjths of the heavens with a telescope having a six- 

 feet opening, and fifty-five feet in length. Thus by the 

 potency of this immense optic tube, in which a man could 

 walk with ease, we see several nebul?e, which up to the 

 present time had defied all our instruments, resolved into 

 dense swarms of stars. ^ 



tube of this instrument being extremely heavy, movement could only be com- 

 municated by a veiy complicated mechanism ; a mass of ladders and masts, form- 

 ing a gigantic pyramid. Its length was nearly 40 feet; its diameter nearly 5. 



' Euler maintained that in order to see the largest animals in the moon, it 

 would be requisite to have a telescope several hundred feet in length. Hooke 

 thought a glass 1(1,000 feet long (nearly two miles) would be necessary, and pro- 

 jected the construction of one. The telescope of Lord Rosse has shown that 

 we can obtain this advantage much more easily. 



"It is," gays Sir David Brewster, "one of onr most marvellous combinations 



