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Mr Vincent, Experiments on Impact. 



Experiments with Paraffin Wax. 



The phenomena of indentation of paraffin wax by a steel sphere 

 seem to be very similar to those in case of lead. 



Fig. 15 shows some sets of readings taken with a steel sphere 

 falling on paraffin. 



V/ ( 



Fig. 15. 



In the case of curve A, Fig. 12, the dents were measured on 

 the paraffin block. The block was used as it comes from the 

 makers except that it was planed up. It was obviously filled with 

 air holes, and the way in which such a material obeys the straight 

 line law is very striking. 



The character of the dent itself is quite different from the 

 dent in lead. In lead no burr is raised round the depression and 

 the sphere fits the hole it makes. In this case there is a very 

 obvious burr produced, and the hole has a radius of curvature 

 greater than that of the sphere which makes it. It was found 

 difficult to measure the dent in paraffin accurately ; but the steel 

 ball has a perfectly regular and easily measured mark on it which 

 is easily measured. This patch is as near as could be determined 

 equal to the dent. 



Curve 15 B is obtained in this way from paraffin wax which 

 had been kept melted for some time to get rid of contained gases. 

 The diameter of the ball was 3'81 cms. 



Curves 15 A and B are both for " hard" paraffin, while curve 

 15 G refers to "soft" paraffin. This block was much larger than 



