VELOCITY OF PROJECTILES, 4J 



The fand remained in the barrel. Its face neareft the blaft was 

 confolidated to a very fmall depth, and I think the mafs ha4 

 |?een removed or elfe jammed more clofely together; for the 

 fpace unoccupied between the place where the breach pin had 

 teen and the furface of the fand was full nine inches. But as 

 the fand was not immediately noticed, I cannot be fure that 

 yone might have been driven or fallen out, during or after the 

 blaft; ; though I am difpofed to think not. 



It muft be remarked, that the powder was a very full charge, Remarks, 

 and that the fand weighed as much as fix muflteb-balls of half 

 an inch diameter. I do not however apprehend that the barrel 

 would have burft with fix balls. 



The blading of rocks, the fplitting of logs of wood, and Ufee, 

 the deflruc^ion of artillery when on the point of being aban- 

 doned to the enemy, are the leading purpofes in which the ap- 

 plication of fand to confine gunpowder is likely to become 

 ufeful. 



IX. 



Report of a Method of mcafuring the initial Velocity of Pra? 

 jecliles difcharged from Fire-arms, both horizontally and with 

 different Elevations^ made to the Phyjical find Mathematical 

 Clafs of the National Inftitute by Mr. Phony, Dec. 11,1 803. 

 Abridged from the Original*, 



AT is not much above fixty years fince experiment began to Robins firft esca- 

 pe applied with fuccefs to' the theory of projediles. Mr. ™™* ( *■ J^ * 

 Benj. Robins, who may be efteemed the firft in this career, tiles by the pen- 

 employed a pendulum to determine the initial velocity of " dulum » 

 mulket balls, meafuring it by the arc of ofcillation. He like- and the recoil of 

 wife meafured the recoil, by fufpending the gun-barrel from \^&tlz\k., 

 the pendulum. 



About ten years after, the Chev. d'Arcy publifhed a feries D'Arcy made 



of experiments in the memoirs of the French Academy of fim,lar "J? 6 "" 

 ... } ments with tw» 



Sciences, in which he employed two pendulums, againft one pendulums. 

 of which the ball was projected, while the other, to which the 

 gun-barrel was fufpended, ferved to meafure the recoil. 



* Journal des Mines 3 No, 92, p. 117, May, 1804. 



Fifteen 



