﻿'>90 Guylord: Cuiuplete Photo -miciogTaphic Apparatus. XVI, 3. 



collar (e) cast in the form of a wlieel. Ou the sliaft {d) is eiit a 

 lonü-itmlinal slot in wliicli a key is placed aiul lipon whicli the screw 



m 



if) impiuges. By this arrangement wlien the screw (/'; is loosened, 

 and tlie collar (e) is turued, the shaft {d) will rise and fall accord- 

 ingly as the collar e is rotated. 



