Mi' Vincent, Experiments on Impact. 345 



For the smaller dents 



6 = 1000, 



so that p = 87 x 10 8 dynes per sq. cm. 



The cases in which the straight line is deviated from are those 

 having small values for p. The specimen of lead giving 



p = llx 10 8 



being the one in which the straight line law was obeyed over the 

 greatest range. 



The time occupied in making the small dents in Fig. 9 is 



8Db 



= l'5x 10 _4 secs. 



Using the same block of lead successive dents were measured 

 and computed as already explained. Values for e were obtained 

 similar to those shown on Fig. 7. 



In the experiments on lead described so far, we have used 

 a steel ball 2*54 cms. in diameter. 



Fig. 10. Steel Balls of different diameters falling through h cms. on to lead. 



In Fig. 10 the results of three sets of experiments are set 

 out. These were performed on the same block. The lead was 

 slowly cooled and showed large crystals on its newly planed 

 surface. Three steel balls were used in these experiments. Their 

 diameters were in the ratio of the numbers 1, 2, 3. The block 

 was replaned after the largest ball was used, but the other two 

 sets of readings were taken on the same surface. 



