[smith] 



DEPRESSION OF DISC UNDER PRESSURE 



221 



it will not affect the curves as they were all taken for increasing p, 

 and if due to back lash the effect is small enough to be neglected. 

 The important point is that after the disc had been subjected to a 

 sufficiently large pressure difference the grease was apparently forced 

 to assume a permanent configuration and does not affect the subse- 

 quent values of the scale deflections. 



4a S'2 



d IN CMS. 



Tables I and II contain the values of p and w for some of the 

 observations. The results of all the observations are plotted on 

 Chart 1. 



It was found that, if for a given value of p, log w was plotted 

 against d, a straight line relationship was obtained. On chart 2 are 

 plotted the values of logio (lOw) against d for seven values of p, viz., 

 100, 150, 200, 300, 400, 500 and 600 mms. of mercury. Values of 

 logio (lOw) were taken to avoid negative characteristics. It is seen 



