109 



T^arying inversely as the square root of the former, and directly as the 

 square root of the latter.^ 



The following experiments were made to ascertain the resistance of 

 the air to bullets of different figures and weights. The bullets were fired 

 at 80 feet distance, from the two-groove rifle into the pendulum, and the 

 velocities calculated from formula (1). 



The constants of the pendulum were— 



g = 32-195 feet. tt = 3-14159. 



T= 1-29 sec. c = 11 in. 



^ = 60 in. Weight of pend. after Exprs. = 51-20 lbs. 



Table Nil.— Minie Bullet at 80 Feet. 



No. 



n. 



6. 



/• 



V. 







In. 



In. 



Ft. 



1. 



501 



11-75 



72-50 



836-42 



2. 



502 



11-87 



71-00 



864-54 



3. 



503 



11-12 



72-00 



800-25 



4. 



504 



11-00 



69-00 



827-68 



5. 



505 



11-25 



71-00 



824-28 



6. 



507 



11-37 



69-00 



860-61 



Mean velocity = 835-62 feet. 



Mean quantity of motion = 83*22 lbs. 



Mean quantity of Work = 1080 lbs. lifted one foot. 



Table NlU.—Sugarloaf Bullet at 80 Feet. 



No. 



n. 



b. 



/. 









In. 



In. 



Ft. 





1. 



516 



11-60 



7] -00 



860 



95 



2. 



617 



11-37 



71-00 



852 



87 



3. 



518 



11-25 



71-00 



846 



60 



4. 



519 



10-62 



67-75 



838 



05 



5. 



520 



11-12 



69-00 



863 



27 



Mean velocity = 852-13 feet. 



Mean quantity of motion = 81-53 lbs. 



Mean quantity of Work = 1079 lbs. lifted one foot. 



* The former of these laws was proved by Mr. Hutton to hold for smooth-bore guns 

 of large size, but the latter did not hold true for his experiments. I suppose the reason 

 it is nearer the truth in rifles is on account of the increased friction in the latter. 



K, I. A. PEOC. VOL. VIII. 



