582 [ASSEMBLT 



Mr. Maj^nard described and illustrated on the black-board the 

 flight of the conical ball. 



On motion of Mr. Fisher, the Club adjourned to the third Mon- 

 day of April, at half-past seven o'clock P. M. 



H. MEIGS, Secretary. 



GUNNERY— COURSE OF A PROJECTILE. 



H. Meigs. 



Galileo, in 1638, demonstrated that course to be parabolic, the- 

 oretically, but not so de facto, on account of the resistance of the' 

 air. 



The force of an eighteen-pounder ball, at the greatest, is found 

 to be 913,190 lbs. per square foot, or more than three ions on one 

 square inch. 



Poirit Blank. — The aim of the piece direct to the white spot on^ 

 the target — from two (o three hundred yards. 



Button's experiments in 1784, '85 and '86, proved that bullets 

 deviate sometimes from 2U0 to 400 yards from the- direct line of 

 fire. 



The enormous velocity of the ball has no effect after the first 

 two hundred or three hundred yards, owing to the prodigious re- 

 sistance of the air. 



Robins showed that a 24 lb. ball, aimed at a target at the dis- 

 tance of 474 yards, must be fired at an elevation of sixteen feet 

 above the mark ! 



The Rijle. — About 1774 rifled cannon were made to carry 

 leaden balls cast with projections on ihem to tit the spiral bore — - 

 that being about one turn from breech to muzzle. They were 

 sighted by means of a sector and an achromatic telescope seven 

 inches long, having cross htiirs in it (as the micrometer has cross 

 cobweb). This gave great accuracy in the firing. 



Muskets were rifled about the same time, by cutting spiral 

 channels in the bore, as a fenials screw, having a little more than 

 oijie turn from breech to muzzle. A leaden ball, larger than the 

 bore, was forced down to the charge of powder, and was both in- 



