1904] Projectiles at Velocities up to 4500 Feet per Second. 269 



When it is considered that the latter were obtained with projectiles 

 weighing many pounds, and the others with shot of 23 and 215 grains 

 respectively, the close agreement of the resistance curves is very 



FIG. 2. 



satisfactory, and shows in a striking way what can be done with small 

 scale experiments when the proper scale of dynamic similarity is 

 employed. 



The extended resistance curve presents no peculiarities, although it 

 can only be expressed at present by an arbitrary formula. But that 

 this should be so is in itself rather remarkable, for it might well have 

 been expected that the resistance would, for high velocities at least, 

 be proportional to the pressure requisite to cause a gas to discharge 

 through a hole in a thin-walled vessel at the speed of the shot. 



Y 2 



