THE SIDEREAL UNIVERSE. 695 



tal discoveries do we owe to them ! They seem with their 

 lynx-eyes to have seen or divined everything. 1 



The first telescope made, Galileo's feeble instrument, only 

 magnified objects seven times, and yet with it he discovered 

 the satellites of Jupiter. 



At present our astronomers explore the stars with instru- 

 ments which multiply 6500 times. Lord Rosse fathomed 

 the depths 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 nebulae, which had defied all our instru- 

 ments, resolved into dense swarms of stars. 2 



1 The first telescope which was constructed of large dimensions was that of Sir 

 William Herschel. He discovered the sixth satellite of Saturn with it. The tube 

 of this instrument being extremely heavy, movement could only be communicated 

 by a very complicated mechanism, a mass of ladders and masts, forming a gi- 

 gantic pyramid. Its length was nearly forty feet; its diameter nearly five. 



2 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 10,000 feet long (nearly two miles) would be necessary, and projected the 

 construction of one. The telescope of Lord Rosse has shown that we can obtain 

 this advantage much more easily. 



"It is," says Sir David Brewster, "one of our most marvellous combinations 

 of art and science." " This magnificent instrument is fixed in the midst of walls 

 which resemble segments of fortifications." The telescopic tube is 55 feet in 

 length, and weighs 14,575 lbs. avoirdupois. With it one can gauge the immeasur- 

 able depths of the heavens. It is thought that by means of this instrument we 

 could easily perceive a monument the size of the pyramids of Egypt, if any existed 

 on the moon. The surface of this planet is there as accurately depicted as a ter- 

 restrial landscape. 



The telescope of Lord Rosse, says M. Babinet, would certainly not show us a 

 lunar elephant, but a troop of animals like a herd of American buffaloes would be 

 quite visible. Troops marching in order of battle would be clearly perceptible. 

 The observatory at Paris, Notre Dame, and the Louvre would be very easily 



