334 



Mr. J. Prescott on the 



K 



5. The curve (fig. 1) shows the relation between ^ an( l 



V for Bashforth's standard shot, which is such that the 

 number of pounds in the weight W is equal to the number 

 of inches in the diameter d. It will be seen from the curve 



Fig. 1. 



/I00G] 2 R 

 I V / dz 















<; 





I 







1 



I 



i 



'■ 















1 * QCBtzzzszaazstS* 

















I 





i 







I 



400 



800 



1200 



1600 



2000 2400 2800 



Curve showing the relation between resistance, R lb., the velocity, 

 V feet per second, and diameter, d inches, for an elongated shot. 



that the resistance is fairly well represented by assuming 

 that R = KV 2 or R = KiV 2 according as V is greater or less 

 than 1060 feet per second, K and K x being a pair of 

 constants. It will be shown in this paper that very good 

 agreement with Bashforth's tables, as well as with the range 

 tables for bullets, can be obtained on these assumptions. 



6. Projectile in a Low Trajectory. — The trajectory is 

 called low if the direction of motion throughout the flight 

 always makes a small angle with the horizontal. 



7. The assumptions we are making concerning the resist- 

 ance will be used in the following forms : — 



WY 2 



B= j- when V>1060 feet per sec. 



9 l 



wys 



and R= — -=- when V< 1060, 



9 h 



W being the weight of the § projectile in pounds, R the 



