408 Mr. L. Gompertz's Method of dcf ending 



Fig. 1 is also a section of a side of a different construc- 

 tion, but inferior, and less applicable, though being more 

 simple and on nearly the same principles, I will describe the 

 nature of that first, or rather both together ; the same rea- 

 soning applying to each. BC is the side forming an acute 

 angle with the water, and extending some way under the 

 water, but not far, as balls do not generally penetrate that 

 part of a ship which is far below the surface of the water ; 

 ST is a board placed as shown, so that there shall be a va- 

 cancy existing between itself and the side of the ship ; diis 

 vacancy grows progressively less upwards, till there is only 

 room left for a ball to pass, and the board is (listened by dif- 

 ferent supports in places to the ship, but these are not put 

 in this figure, as they would hide the operation. The part 

 W is so curved as to return the balls after they have struck 

 the inclined part ; but as in this construction the return part 

 might be struck by balls coming directly against it, without 

 their having struck the inclined part, it might be required 

 to make the most perpendicular place of it near P strong 

 enough to resist the balls, this portion of the curve being very 

 small. The effects then will vary in different cases, and will 

 depend on the hardness and on the elasticity of the material 

 of the side of the ship, and of the ball ; also on the force with 

 which the balls are fired : the following results, it seems, would 

 then be produced. 



Case ] . If the ball and the side were perfectly elastic, and 

 of sufficient hardness not to be broken, or if only the side 

 were perfectly elastic, then, according to the established law, 

 the ball would be reflected backwards and forwards in fig. 1 , 

 between the side C B and board S T, and in fig. 3 between 

 IC and IH, at equiangles, and would not follow the shape of 

 the curve; and if the force of the ball should not be too 

 much destroyed by the operation, it would at last be reflected 

 off, though most likely not in a proper direction to reach the 

 enemy. 



2dly. If neither the side nor the ball should possess any 

 elasticity, and the side were perfectly hard, whether the ball 

 should be hard, or whether it should be soft (so as to indent), 

 it would be turned out of the direction, and would in fig. 1, 

 if struck at H, proceed up the inclined side BC, and would 

 follow the shape of the curve W (the motion of the centre 

 being shown dotted at IPQ), and it would then return to X 

 and in fig. 3, if it should strike at H, it would proceed in the 

 direction of the whole shape N WAL (the motion of the cen- 

 tres being shown dotted at HIJR) ; and it would return as 

 the arrows point : but if, in fig. 1, it should strike at V, or in 



fiti". 



