The Berthon Telescope Stand. 



203 



THE BERTHON TELESCOPE STAND. 



We mentioned in the "Notes and Memoranda" of our last 

 number that Messrs. Home and Thornthwaite had brought out 

 an admirable telescope stand, the invention of the Rev. E. L. 

 Berthon, with whose name our readers will be familiar. The 

 nature of the invention will be rendered intelligible by the 

 annexed woodcut. The pillar is formed of iron handsomely 

 bronzed, and the telescope is fixed in the usual way to a cradle, 

 having a vertical motion only. Under each foot of the stand 

 is a roller, so placed that a gentle pressure imparts a horizontal 

 circular movement, and enables the telescope to be readily 

 pointed in any azimuth, and to follow a moving object, such as 

 a ship or a star, with great steadiness. Until Mr. Berthon' s 

 plan has been tried, no one would imagine how firmly the 

 instrument stands when not touched, and yet how easily a 

 touch in the right direction imparts a horizontal movement. 



The vertical movement affords another specimen of Mr. 

 Berthon' s aptness for devising very simple means of obtaining 

 his object. At a is seen an upright steadying rod, composed of 

 a screw working through a nut, which carries it up or down 

 the tube attached by a hinge joint to the foot of the stand. 

 By turning the nut at a to the right or left, a beautifully 

 smooth vertical adjustment is obtained. It is far better than 

 the usual rack and pinion, and gives a slow motion. When a 

 quick one is desired, a collar covering the nut at a is pressed 

 downwards, when the nut itself, being composed of two pieces 

 attached to springs, flies open, as shown at b. The telescope 



