420 



Mr. H. Pealing on an Anomalous 



Fig. 1 and fig. 2 curve 1 give typical graphs obtained by 

 plotting the relative values of the rigidity as ordinates and 



1*3 



Kg. l. 



•0 



f- 







w 



14 



the weights supported as abscissa?. Fig. 1 -was for a phosphor* 

 bronze strip 0*0010 cm. thick, and fig. 2 for a strip 0*0043 cm. 

 thick. In fig. 2 it will be noticed that the restoring couple 

 per unit angle of twist for a small load is only one third of 

 that for a heavy load. With the thin strips the rigidity 

 varied very rapidly for small loads, as is shown in fig. 1, 

 decreasing as the load is decreased, but for very small loads 

 increasing again. The discrepancy was different for different 

 strips of the same thickness even when they were cut off the 



same length, but the maximum ratio of : - was about 3. In 



. . 7 1 



general fig. 1 is typical of the behaviour of all the thin 

 strips and fig. 2 of the thick strips, though the amount of 

 variation was different in different specimens. 



