Bending and Twisting Moments simidtane 



501 



on a steel tube G inches long, having an external diameter of 

 0*748 inch and a wall-thickness of 0*024 inch. 



The calibration value of the eyepiece scale where referred 

 to the graduated circle was found to be 10*35 divisions for 

 one minute of arc. The following readings were obtained: — 



Twisting 





Moment. 

 Inch-Pounds. 



Reading A. 











100 



237 ~ 237 



200 



474 -» 



300 



712 " 238 



400 



920 ~ 238 



500 



1188 ~ 238 



and the value of C — 12,400,000 in inches and pounds was 

 determined from these observations. 



The observation wire was then rotated into a horizontal 

 position and set at a distance of one inch from the central 

 plane. Bending moments were applied and readings were 

 observed as follows : — 



Bending 







Moment. 

 Inch-Pounds. 



Beading 



A. 













103 



59 



-59 



200 



118 



-59 



300 



178 



-60 



400 



239 



-61 



500 



297 



-oS 



from which the value of E. was calculated. The angular 

 change 2 of one end of the specimen was determined 

 from the readings R by the formula R=2#0 2 > where #=1 

 inch, and account was taken of the fact that the effective 

 radius of arc was changed from i\ to r 2 in the new adjust- 

 ment of the instrustment so that the angle 2 must be 



