98 



KENNELLY-TAYLOR— EXPLORATIONS OVER [April .2, 



A stout brass bridge is fastened to the sides of the rectangular 

 frame. At the center of this bridge is the mirror-holder shown in 

 detail at Fig. 3. The mirror-holder slides in a groove provided in 

 the bridge, and is clamped therein by a clamping screw 5". A fine- 

 motion screw M is also provided, for adjusting the position of the 

 mirror. One turn of M advances the mirror 0.8 mm. (1/32 inch). 

 By means of an auxiliary mirror fastened beneath the top of the 

 screw M, the angle through which the screw is advanced may be 



Top K/lfM' of Brid^f 

 tind /Mirror Holder. 



Enlarged S/iew 

 of Stirrup anti 

 flirror. 



Mirror for measuring 

 An^Ie turned by Adjusf-fn^ 

 Screw in Calibrar/on. 



riG. 3 



SECTION ■ TH HOUGH 

 DIAPHRflCM. 



Apparatus for Exploring the Visratiom 

 ^ ems. OF Diaphragms. 



measured, for calibrating the indications of the instrument. Ad- 

 justment can be made to i deg. of rotation, or 2.2 ^u,; i. e. ( -^ mm. j 

 assuming that backlash is guarded against. 



