MEASURING THE VIBEATOUV I'EKIODS OK TUNING-FOEKS. 



57 



wave iu the trace of tlie fork, wo liave the time it took the ball to go over the kuown distance from 

 the wire w to the target T. 



As an example of such work, we here give ex])erimeiits we made on tlie velocity of the rifle- 

 ball of A5 inch caliber of the United States Army cartridge. This ball weighs 405 grains, and the 

 powder driving it weighs 70 grains. 



Table XVI. 



Xiiiiilior of experiment. 



(1) 

 (2) 

 (3) 

 (•1) 

 (5) 

 (6) 





11.31 

 11.34 

 11.30 

 11. '.^8 

 11.35 

 11.3-2 



c 



a' 



Seconds. 

 .04418 

 . 04429 

 .04414 

 . 04406 

 . 04433 

 . 04421 



Feet. 

 1,:«8.0 

 1,354.7 

 1,359.3 

 1,361.7 

 1, 3.53. 3 

 1, 357. 1 



1,3.57.3 



Feet. 

 +0.7 

 —2.6 

 +2.0 

 +4.4 

 —4.0 

 —0.2 



The tifth column gives the ditterences of the separate determinations, and 1,3.57.3 feet the mean 

 velocity of the ball per second. The average difference amounts to only 2.3 feet. 



EXPERIMENTS WITH THE CHEONOSCOPE ON THE VELOCITIES OF FOWLING-PIECE SHOT OF 

 VARIOUS SIZES PROJECTED WITH VARIOUS CHARGES OF POWDER FROM 12 AND 10 GAUGE 

 GUNS. 



The guns used iu these experiments wei-e "choke bore," of the Colt Arms Manufacturing 

 Company, of Hartford, Conn. They had rebounding locks. The primary current of the induc- 

 torium passed through a break-piece fixed under the rebounding hammer, so that at the instant 

 the cartridge was exploded the electric current iu the primary circuit of the inductorium was 

 broken and then immediately formed again. The current which passed through this break-piece 

 was led by a wire to an upright piece of tin plate, whose front surface leaned against a thick 

 copper wire. Another wire led from the tin plate (which stood in a shallow trough of mercury) 

 back to the battery. 



The following tables give the results of our experiments: 



TABLE XVII. 



[lO-gauge Colt gun; 5 drams Curtis & Harvey powder; l^^-ounce shot.] 



S. Mis. m- 



