MEASURING THE STRIKING FORCE OF SHOT. 325 



liability of the substitute. The results do not seem to 

 me to bear out such a conclusion. In the first place, 

 the principle of the thing is at fault. The stroke of 

 the hammer and that of the pellets of shot bear 

 scarcely any analogy to each other. The one is the 

 effect of a highly elastic, comparatively heavy body 

 moving at a slow rate of speed, and its character is 

 akin to pressure succeeding impact ; the other that of 

 a number of very light, almost inelastic bodies travel- 

 ling with exceedingly rapid and varying velocities, 

 and the blow an irregular succession of short impulses. 

 No regard is paid to the laws of resistance to com- 

 pression ; the amount of distortion suffered by the 

 hammer (?) or shot ; the duration of the impact or 

 pressure, or the pliability of the target. Can all these 

 be utterly ignored ? Does not the rapidity of the 

 transmission of the force from one particle to another 

 have its influence ? Is no importance to be attached 

 to the position of the strokes on the plate ? In other 

 words, is it reasonable to suppose that a pellet or a 

 number of them, striking near the edge of the disk, 

 will have an equal effect in moving it back with a sim- 

 ilar force acting nearer the centre ? Does it not make 

 some difference too in result as to whether the pellets 

 strike together, all at one instant, or in succession ? I 

 leave these questions for the reader to answer, and 



