118 
GUN-COTTON. 
same space as the gunpowder with one-fourth of the weight of gun-cotton made up in 
the bobbin as described, and he will fire the same shot at the same speed. This is 
speaking in a general way, for it may require in some guns as much as | of the weight 
of gunpowder and -fi the bulk of charge to do the same work; a little experience will 
settle the exact point, and greater experience may enable the gun-cotton to exceed the 
performance of the gunpowder in every way. 
The fifth principle in the use of gun-cotton is that involved in its application to 
bursting uses. The miner wants the stratum of coal torn from its bed, or the fragment 
of ore riven from its lair; the civil engineer wishes to remove a mountain of stone out 
of the way of a locomotive engine ; and the military engineer to drive his way into the 
fortress of an enemy, or to destroy the obstacles purposely laid in his way. This is a 
new phase of duty for gun-cotton—it is the work of direct destruction. In artillery 
you do not want to destroy directly, but indirectly. You don’t want to burst your gun, 
nor even to injure it; and, we have seen, in order to secure this, you have only to give 
it room. 
The fifth principle therefore is, to make it destructive—to cause it to shatter every¬ 
thing to pieces which it touches, and for this purpose you have only to deprive it of 
room. Give it room, and it is obedient; imprison it, and it rebels. Shut up without 
room, there is nothing tough enough or strong enough to stand against it. 
To carry this into effect, the densest kind of gun-cotton must be used. It must no 
longer consist of fine threads or hollow textures wound on roomy cores. All you have 
to do is to make it dense, solid, hard. Twist it, squeeze it, ram it, compress it; and in¬ 
sert this hard, dense cotton-rope or cylinder or cake in a hole in a rock, or the drift of a 
tunnel, or the bore of a mine; close it up, and it will shatter it to pieces. In a recent 
experiment, G ounces of this material set to w r ork in a tunnel not only brought down 
masses which powder had failed to work, but shook the ground under the feet of the 
engineers in a way never done by the heaviest charges of powder. 
To make gun-cotton formidable and destructive, squeeze it and close it up; to make 
it gentle, slow, and manageable, ease it and give it room. To^make gunpow T der slow 
and gentle, you do just the contrary: you cake, condense, and harden it to make it slow, 
safe for guns, and effective. 
To carry out this principle successfully, you have to carry it even to the extreme. 
Ask gun-cotton to separate a rock already half-separated, it will refuse to comply with 
your request. Give it a light burden of earth and open rock to lift, it will fail. If you 
want it to do the work, you must invent a ruse,—you must make believe that the work 
is hard, and it will be done. Invent a difficulty and put it between the cotton and its 
too easy work, and it will do it. The device is amazingly successful. If the cotton have 
work to do that is light and easy, you provide it with a strong box, which is bard to 
burst,—a box of iron for example; close a small charge, that would be harmless, in a little 
iron box, and then place that box in the hole where formerly the charge exploded harm¬ 
less, and in the effort it makes to burst that box, the whole of the light work w'ill dis¬ 
appear before it. 
Of the effect of such an explosion, an illustration accompanies this paper. The two 
drawings represent two views of a stockade, in close contiguity to which a charge of 
25 lbs. of gun-cotton, placed in an iron box, was employed, and the consequences will be 
seen in the two rent and shattered trees, the largest 20 inches in diameter, which were 
not only removed from their places, but by some unexplained action shattered through¬ 
out into matchwood. This explosion was the first trial of English-made gun-cotton, 
and w r as made at Stowmarket, in spring. 
It is, therefore, the nature of gun-cotton to rise to the occasion and to exert force 
exactly in proportion to the obstacle it encounters. For destructive shells this quality 
is of the highest value. You can make your shell so strong that nothing can resist its 
entrance, and when arrived at its destination no shell can prevent its gun-cotton charge 
from shivering it to fragments. 
These are the main principles in the mechanical manipulation of gun-cotton which 
will probably render it for the future so formidable an instrument of war. Resistances 
too great for gunpowder only suffice to elicit the powers of gun-cotton. On the other 
hand, in its elementary state, as the open cotton-yarn, it is playful, slow, gentle, and 
obedient; there is scarcely any mechanical drudgery you can require of it that it is not 
as ready and fit to do as steam, or gas, or water, or other elementary power. 
