OF ARTS AND SCIENCES. 377 



great advance in equalizing the forces between the breech and the 

 muzzle of the gun. But let us see what it costs in loss of force from 

 the use of the coarse powder. Taking the mean of these two ex- 

 tremes as the true force in both cases, we have 51,800 -f- 6,700 -f- 2 = 

 29,250 for the mean force of the 8 lbs. of fine powder, and 31,950 -j- 

 5,150 -J- 2 = 18,550 for the mean force of the large powder; from 

 which it will be seen that it will require 12^ lbs. of the coarse powder 

 to produce the same force upon the shot that is produced by 8 lbs. of 

 fine powder. The long and short of this whole matter of using the 

 powder in lumps rather than grains is a mechanical adulteration, and 

 produces the same effect, namely, a slow combustion, such as may be 

 produced by making the powder of materials chemically adulterated, or 

 by mixing a portion of clay with the paste, or by moistening good 

 powder before using it. This reduction of force may be carried to any 

 extent by increasing the size of the grains or lumps, or by making it 

 in perforated cakes, as Captain Rodman actually proposes to do. 



But suppose that Captain Rodman's ideas of the advantage of a slow 

 development of the force could be carried out, of what use would it be ? 

 I assert, although I am not yet quite prepared with a formal demon- 

 stration of it, that the same, or very nearly the same, quantity of iron 

 will be required in the gun, the iron being used in the manner pointed 

 out by me in 1855, to give the same velocity to a given shot, under 

 whatever law the force is developed, between the limits of the quickest 

 powder now used, and one of equable force development ; and that, to 

 produce this force with the least expenditure of powder, the develop- 

 ment of the force should be made as quick as possible. 



I now pass to an examination of Captain Rodman's proposal to use 

 hollow shot. Having, as it seems to me, laid his powder under as 

 great a contribution as it would bear, to avoid putting too much 

 stress upon his gun, he proceeds to put the same tax upon his shot, and 

 he assesses it by taking 9 inches from the heart of every 15-inch shot, 

 thus reducing its weight from about 425 pounds to about 320 pounds. 

 In the mediaeval times, when guns and gunnery were in their infancy, 

 stone balls were used. The lightness of this material saved the imper- 

 fect homhards from destruction. The effect of these balls was of course 

 very small, compared with the heavy, solid iron shot brought into 

 use in a later age. Are we to return to the mediseval practice ? This 

 certainly seems a step in that direction. 



Sir Howard Douglass, in speaking of the terrible effect of the fire 

 VOL. V. 48 



