

SECTION V. 



RESOLUTION OF REMABKABLE NEBULJB. 



THE last few years have been remarkable for the pro- 

 duction of the largest telescope ever manufactured. Sir 

 "William Herschel constructed, with his own hands, tele- 

 scopes of 20 and 40 feet focus, with which he made some 

 of the most brilliant discoveries recorded in the history 

 of astronomy. But quite recently, the Earl of Kosse has 

 completed a telescope still more gigantic than the largest 

 of Sir William Herschel. He had previously constructed 

 a telescope of three feet aperture, which, received the 

 highest commendation from Dr. Robinson and Sir James 

 South. In 1842, he commenced another of far superior 

 dimensions, whose speculum was six feet in diameter, 

 and weighed three tons. The materials of which it is com- 

 posed are copper and tin, united in the proportion of fif- 

 teen parts of copper to seven of tin. The process of 

 grinding was conducted under water, and the moving 

 power employed was a steam engine of three horse power. 

 The substance made use of to wear down the surface was 

 emery and water, and it required six weeks to grind it to 

 a fair surface. 



The tube of the telescope is 56 feet long, and is made 



