g4 CHARGES OF GREATEST EFFICACY FOR ARTILLERY AT SEA, 



that is, the cbarj^e varies as the space to be penetrated 

 ajid weight of the ball directly, and dianiett-r of the ball 

 inversely. 



But the charge by the problem being to produce the 

 greatest effect possible in the destruction of the vessel ; S in 

 the above formula must always be put equal to the given 

 thickness of the pide; since it is well ascertained, that, for 

 a shot to produce the most damage to any splintering ob- 

 ject, such as oak; it must lose all its motion just as it 

 ceasys to be resisted by tiie object, which happens when the 

 ball has forced its first hemisphere out of the farther surface 

 of it. And the quantity of motion destroyed during the 

 penetration of the first hemisphere of the ball into, and the 

 exit of the same out of the object is precisely equal to wbat 

 would be destroyed during- the penetration of the ball 

 through one of its radii, if the quantity of resisting surface 

 was equal to half its entire superficies. Hence the charge 

 in question will be 



•045 X -^ 



S being tlie thickness of the side of the ship; to the weight 

 of the ball; and D its diameter. 



ExAiVrPLE. 



Example An enemy's ship is in sight ; required the charge for the 



42 pounder guns to destroy her as quickly and completely 



as possible, when the ships have approached near to each 



other. The side of the enemy's vessel, a 74, being ]| foot 



thick of oak timber. 



.. The diameter of a 42 pounder of cast iroa being = '557 



feet ; we get 



Sjc 1 X 42 



♦045 X -FT- = -045 X ~ = 5-93806 lbs. 



D '557 



or, 5 lbs, 15 0ZS. for the weight of the charge sought. 



Tab LB 



