106 



I shall first give the details of the experiments, and then mention the 

 principal deductions which may be obtained from them. 



The formula used in calculating the velocity is the following — ■ 



V = —r X no. 

 Trfc 



(1) 



where v 

 T 



f- 



velocity of bullet in feet per second, 

 time of oscillation of pendulum, 

 distance of centre of gravity from axis of suspension, 

 ratio of circumference of a circle to its diameter, 

 distance from axis of gun attached to pendulum to axis of 

 suspension. 



c = distance from axis of suspension to point of attachment of 



tape, by which the recoil is measured. 

 n = ratio of weight of pendulum to weight of bullet. 

 i = chord of arc of recoil, measured by tape. 



The two-grooved rifle barrel being firmly strapped with iron plates to 

 the pendulum, the constants of the pendulum were carefally determined, 

 and were as follows : — 



32-195 ft. 7r = 3-14159 Weight of pend. = 36-75 lbs. 

 T= 1-29 sec. /= 75-25 in. 

 a = 57-39 in. e = 78-25 in. 



From these data we obtain (1) 



V = 0-12894 X nh. (2) 



The following Tables contain the results of the experiments made on 

 the recoil of the two-grooved rifle with the three bullets already de- 

 scribed : — 



Table I. — Minie Bullet. 



No. 



n. 



b. 



V. 







Id. 



Ft. 



1. 



369 



17-50 



833 



2. 





18-25 



869 



3. 





17-25 



821 



4. 





18-50 



881 



5. 





18-00 



857 



6. 





17-25 



821 



Mean velocity = 847 feet per second. 



Mean quantity of motion, measured in avoirdupois pounds, moving 

 through 1 foot per second = 84*33 lbs. 



Mean quantity of Work = 1109 lbs. lifted one foot. 



* Poissou, "Traite de Mechanique," vol. ii., p. 119. 



