1912] 



nn the Pressure of a Blow. 



283 



will 1)0 seen that the t\)rce so produced has the characteristics of a 

 blow, namely, great intensity and short duration, if such a cylinder 

 of irun-cotton weighing one or two ounces be placed in contact with 



ROD STRUCK AT ONE END 





ComjiTi 



esswrv. ^ZZX TensioTv: ES3 



Fig. 3. 



a mild steel plate, the effect, if the plate be half an inch thicker less, 

 will be simply to punch out a hole of approximately the same dia- 

 meter as the gun-cotton, just as though it had been struck by a pro- 

 jectile of that diameter. But if the plate be three-quarters of au inch 



