CIIiRfJES OF GREATEST EFFICACY FOR ARTILLERY AT SEA, g3 



These belnor premised, I now proceed to resolve the fol- 

 lowing important 



Problem. 



To find a frpneral Formula, which shall express the Charge of To find the 

 Powder for any given Piece of Artillery to produce the ^^^'-^^"^^ ^V'l 

 greatest Dratrnction possible to an En°my''s Ship cf 5ea ; do nic^t exe- 

 it being supposed of Oak Substance of given Thickness, ^^^^°^» 

 and at a Distance not affecting the initial Velocity of the 

 Shot, 



By the last of the foregoing lemmata we have generally 



V :=. ( " ^ ^ . Also the charges of powder vary as 



\ sD N r J 

 the squares of the velocity and weight of the ball jointly. 

 Hence, since it has been determined from experiment, that 

 a charge of half a pound impelled a shot weighing lib. with 

 a velocity of I6OO feet per second ; we shall, considering 



V the velocity of any ball imping'ng on the side of the 



vessel, have for the expression of the charge impeUing it 



, „ S R </7i w* w 



through the space S r: -^-^-_^_ . 



Now to apply this in the present instance it is first neces- 

 sary, that a case be known concerning the penetration of a 

 given shot into oak tubstjuce. Such a case is presented at p, 

 273 of Dr. Hutton's Robins's New Principles of Gunnery. It 

 is there asserted, th;-.t an 18 pounder cast iron ball penetrated 

 a block of well seasoned oak (such as ships of war are gene- 

 rally built with) to the depth of 3| inches when fired with 

 a velocity of 4-00 feet per second. Making therefore this 

 the standard of comparison for all cases where the object is^. 

 of oak substance, we shall have for the charge generally, 

 400 « X -42 SRnw 



2 X lOOO* X ^T ^ D N r 

 or, because the balls are of the same specific gravity, and 

 the substance the same, or R s: r, and N r: n ; it will be 



400* X -42 Sm> ^.^ . -Sm? 



= '045 X 



2 X 1600* X ^T I> i> 



G2 that- 



