420 



GUN COTTON. 



weight of gun cotton made up in the bohbin 

 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 one-third of the weight of gunpowder and 

 eleven-tenths 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. 



Thejifth 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 noth- 

 ing 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 insert 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, 6 oz. of 

 this material set to work 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 destruc- 

 tive, squeeze it and close it up ; to make it gentle, 

 slow, and manageable, ease it and give it 

 room. To make gunpowder 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 hard 

 to burst, a box of iron for example ; close a 

 small charge, that would be harmless, in a lit- 

 tle 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 will disappear 

 before it. 



The first trial of English-made gun cotton 

 was made at Stowmarket in the spring of 1861. 

 A charge of 25 Ibs. not only destroyed a tree- 

 stockade, but shattered it into matchwood. 



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 pre- 

 vent its gun-cotton charge from shivering it to 

 fragments. 



These are the main principles in the mechan- 

 ical manipulation of gun cotton which will 

 probably render it for the future so formidable 

 an instrument of Avar. Resistances too great 

 for gunpowder only suffice to elicit the powers 

 of gun cotton. On the other hand, in its ele- 

 mentary state as the open cotton yarn, it is 

 playful, slow, gentle, and obedient; there is 

 scarcely any mechanical drudgery you can re- 

 quire of it that it is not as ready and fit to do 

 as steam, or gas, or water, or other elementary 

 power. 



As to the nature and source of this amazing 

 power of gun cotton, Mr. Russell, as a mechanic, 

 thus undertakes to reply : " Who shall say what 

 takes place in that pregnant instant of time 

 when a spark of fire enters the charge, and one- 

 hundredth part of a second of time suffices to 

 set millions of material atoms loose from fast 

 ties of former affinity, and leaves them free 

 every one to elect his mate, and uniting in a 

 new bond of affinity, to come out of that 

 chamber a series of new-born substances? 

 Who shall tell me all that happens then ? I 

 will not dare to describe the phenomena of 

 that pregnant instant. But I will say this, 

 that it is an instant of intense heat one of its 

 new-born children is a large volume of steam 

 and water. "When that intense heat and that 

 red-hot steam were united in the chamber of 

 that gun and that mine, two powers were met 

 whose union no matter yet contrived has been 

 strong enough to compress and confine. When 

 I say that a gun-cotton gun is a steam-gun, and 

 when I say that at that instant of intense heat, 

 the atoms of water and the atoms of fire are in 

 contact atom to atom, it is hard to believe that 

 it should not give rise to an explosion infinitely 

 stronger than any case of the generation of 

 steam by filtering the heat leisurely through the 

 metal skins of any high-pressure boiler." 



