Charges of greatest Efficacy for Artillery at Sea . 231- 
=.045 x - — & being the thickness of the side 
of the vessel, w the weight of the ball, and D its diameter. 
We have supposed, that the resistance opposed to the 
balks motion is uniform throughout the entire penetra- 
tion ; which is not strictly true ; since that resistance de- 
pends partly on the quantity of the surface resisted, which 
continually varies until the ball has penetrated to the 
depth of its radius ; when it continues uniform till it ar- 
rives at the further surface of the object ; where the re- 
sistance again commences its variation. These deviations 
from uniformity are about sufficient to set against that of 
the law of variation of the charges before mentioned ; the 
velocities from them falling somewhat short of the law 
there prescribed after a certain charge. 
Example I. 
Jin enemy’s skip is in sight; required the charge for 
the 4 2-pounder guns to destroy her as quickly and com- 
pletely as possible when the ships have approached near 
to each other : the side of the enemy’s vessel (a seventy- 
four) being 1 ifoot thick of oak timber . 
The diameter of a 42-pounder of cast-iron being = *55’7 
r 
foot; we get *045 x — rz 6*88806 lbs. or 6 lbs. 
14 ozs. for the weight of the charge required, 
TABLE 
Containing the various charges for the 12-, 18-, 24-, 32-, 
36- and 42-pounder guns, for producing the greatest 
effect in all cases of action : the substance or object 
being of oak materials, and its thickness together with 
the radius of the ball from 1 foot to that of 5 feet, re- 
gularly increasing by 1 in the inches., 
Vol. i. x n 
