THE 



PHILOSOPHICAL MAGAZINE. 



JULY 1798. 



I. Defer ipt ion of the Mechanifm of a refccling Tele/cope twen- 

 ty-Jix Feet in Length, conjlrucled near Kiel in Holjtein, by 

 ProfeJJor Schrader. From the Account, publijhed in 

 German, by the Frofejfot. 



x\.N hexagonal frame ABCD, (Plate V.) formed of ten 

 inch fquare beams, joined together, refts upon twelve ftrong 

 ports driven into the ground. On the fmaller hexagon of this 

 frame ftands the under part of the building aaaa, which rifes 

 to the height of fourteen feet, and is fupported by braces or 

 fpurs. On the beams which compofe the upper frame of 

 this part of the building lies a horizontal wheel, 12 feet in 

 diameter, which is made fart by means of iron fcrews. A 

 fmall hexagonal cabin of the like diameter, and y\ feet in 

 height, forms the moveable upper part of the whole build- 

 ing, to which is affixed the mechanifm that ferves for the 

 motion of the telefcope. 



Through the middle of the fmall cabin arifes a very 

 ftrong axle b b, the upper part of which b may be feen pro- 

 jecting above the flat top of the cabin. At c the axle turns on 

 a fteel gudgeon which moves in a focket, fitted into a ftrong 

 beam dd, moveable in a horizontal direction. This beam, 



Vol. I. I by 



