RESOLUTION OF REMARKABLE NEBULJS. 197 



of wood one inch thick, and hooped with iron. The 

 diameter of this tube is 7 feet. At 12 feet distance on 

 each side of the telescope, a wall is built, 72 feet long, 48 

 high on the outer side, and 56 on the inner, the walls be- 

 ing 24 feet distant from each other, and lying exactly in 

 the meridian. "When directed to the south, the tube may 

 be lowered till it becomes almost horizontal ; but when 

 pointed to the north, it only falls till it is parallel with 

 the earth's axis. Its lateral movements take place only 

 from wall to wall, and this commands a view for half an 

 hour on each side of the meridian ; that is, the whole of 

 its motion from east to west is limited to 15 degrees. The 

 expense of this instrument was not less than twelve thou- 

 sand pounds. It has a reflecting surface of 4071 square 

 inches, while that of Herschel's 40 feet telescope had only 

 1811 square inches. 



In March, 1845, Sir James South made a trial of this 

 telescope, and gives the following account of his observa- 

 tions : " Never before in my life did I see such glorious 

 sidereal pictures as this instrument afforded us. The 

 most popularly known nebulse observed were the ring 

 nebula in the Canes Yenatici, which was resolved into 

 stars with a magnifying power of 548, and the 94th of 

 Messier, which is in the same constellation, and which 

 was resolved into a large globular cluster of stars, not 

 much unlike the well-known cluster in Hercules. On 

 subsequent nights, observations of other nebulae, amount- 

 ing to some thirty or more, removed most of these from 

 the list of nebulas, where they had long figured, to that 



