247 



Hammer No. 1 was a high-grade machinist hammer. 



Hammer No. 2 was a claw hammer purchased as a high-grade tool. 



Hammer No. 3 was a lower-grade machinist hammer. 



Hammer No. 4 was a cast-iron hammer purchased at a five and ten 

 cent store. 



The steel sphere used in the above experiment, when tested with a 

 similar sphere, gave an average of approximately two per cent energy 

 loss. 



Conclusion: The experiment justifies the conclusion that high-grade 

 steel hammers conserve to a much larger degree the kinetic energy of 

 a blow than low-grade cast-iron hammers. 



