1916] on Polarized Light and its Applications to Engineering 58D 



in deforming the diaphragms is stored therein, and tends to bring 

 the moving system back to its initial position, errors are avoided, 

 and a very accurate measure of the applied load is obtained. 



The methods adopted for obtaining the stress distribution were 

 similar to those described above, and experiment showed that the 



31 



B 



^ 



Fig. 



lines of stress formed an orthogonal system very nearly directed in 

 the line of load and perpendicularly thereto. 



In order to facilitate the measurements it was found convenient 

 to suspend the lateral extensometer X, from a three-point support 

 (Fig. 9), borne by a block sliding upon the vertical pillars P^, Po of 

 the testing machine, and having two cross horizontal slides B and 



