418 



GUN COTTON" 



of gun cotton, the workmen may proceed in their 

 work at once without inconvenience. 



In casemates of fortresses, gunpowder fills the 

 casemates with foul smoke, and the men speedi- 

 ly sink under the exertion of quick firing. By 

 using gun cotton it was ascertained that the 

 men could continue their work unharmed for 

 double the quantity of firing. This is partly 

 attributed to the greater heat, and partly to the 

 foulness of the air produced by gunpowder. 



But it is under the decks of our men-of-war 

 that the greatest benefit is likely to arise from 

 gun cotton. Not only does the smoke of a 

 broadside fill the between decks with hot and 

 foul air, but the smoke of the windward gun 

 blinds the sight, and hinders the aim of the lee- 

 ward. When there is no smoke, as with gun 

 cotton, the aim of every gun may be precise and 

 deliberate. The diminished heat between decks 

 will also tell powerfully in favor of gun cotton. 

 In our armour-plated ships also there is more 

 value in breech-loading guns than in any other 

 use of artillery. It is one of the necessities of 

 breech-loading mechanism that it be kept clean, 

 and nothing tends more to derange its perfect 

 action than the greater heat which gunpowder 

 imparts to the gun from which it is fired. 



That gun cotton has the convenience of not 

 heating the gun has been thus proved: 100 

 rounds were fired in 34 minutes with gun cotton, 

 and the temperature of the gun was raised 90 

 dcg. 100 rounds were fired with gunpowder, 

 and triple the time allowed to cool the gun, 

 which nevertheless was heated so much as to 

 evaporate water with a hissing sound, which 

 indicated that its temperature was much above 

 212 deg. Under these circumstances the firing 

 with gunpowder had to be stopped, while that 

 with gun cotton was comfortably continued to 

 180 rounds. 



It is also a matter of practical convenience 

 that gun cotton, insomuch as it is lighter, can 

 be carried more easily and further than gun- 

 powder ; and it may be wetted without danger, 

 so that when dried again in the open air, it is 

 as good for use as before. 



3. We have now to ask, Is it cheaper ? The 

 answer to this question must be qualified 

 pound for pound it is dearer ; we must, there- 

 fore, judge of its cheapness by its effect, not by 

 weight merely. But where it does six times 

 as much work, it can then be used at six times 

 the price per pound, and still be as cheap as 

 gunpowder. As far as we yet know, the prices 

 of gun cotton and gunpowder are nearly equal, 

 and it is only, therefore, where the one has 

 advantages and conveniences beyond the other, 

 and is more especially suited for some specific 

 purpose, that it will have the preference. 

 Effective cheapness will therefore depend 

 mainly on which of the two does best the par- 

 ticular kind of duty required of it. 



To illustrate how curiously these two powers, 

 gun. cotton and gunpowder, differ in their 

 nature, and how the action of gun cotton may 

 be changed by mechanical arrangements, we 



may take one kind of work that is required of 

 both : If a General wants to blow open the 

 gates of a city, he orders an enterprising party 

 to steal up to the gate, with a bag containing 

 100 Ibs. of gunpowder, which he nails to the 

 gate, and by a proper match-line he fires the 

 gunpowder and bursts open the gate. If ho 

 nailed a bag of gun cotton of equal weight in 

 the same place and fired it, tire gun cotton 

 would fail, and the gate would be uninjured, 

 although the 100 Ibs. of gun cotton is sixfold 

 more powerful than the gunpowder. Here, 

 then, gunpowder has the advantage both 

 weight and effect considered. 



But the fault here lies not in the gun cotton, 

 but in the way of using it. If, instead of 100 

 Ibs. of gun cotton in a bag, 25 Ibs. had been 

 taken in a proper box made for this purpose, 

 and simply laid down near the gate and not 

 even nailed to it, this 25 Ibs. would shiver the 

 gate into splinters'. The bag which suits the 

 powder happens not to suit the gun cotton. 



Gun cotton is, therefore, a power of a totally 

 different nature from gunpowder, and requires 

 complete study to know its nature and under- 

 stand its use. It appears that both gunpowder 

 and gun cotton have special qualities, and may 

 be peculiarly suited for peculiar uses. It is the 

 duty of a wise people to make use of both to 

 the ends they each suit best, without prejudice 

 arising from the accident of novelty or an- 

 tiquity. 



The nature of gun cotton requires a double 

 study, chemical and mechanical. It is not like 

 steam, the same substance, whether in the form 

 of ice, or water, or steam. It is one substance 

 when as gun cotton it enters the gun, and quite 

 a different one when it has exploded and leaves 

 the gun. Not only are the solids which enter 

 converted into gas, but they form totally new 

 combinations and substances. So that the 

 marvellous changes which the chemist effects 

 by the magic of his art take place in an instant 

 of time, and during that almost inconceivably 

 minute period of time, in a laboratory intensely 

 heated, old substances are dissolved, their ma- 

 terial atoms are redistributed, each atom re- 

 leased selects by natural affinity a new partner, 

 these new unions are cemented, and at the end 

 of this prolific instant totally new combinations 

 of matter, forming what we call new substan- 

 ces, issue from the gun. It so happens that of 

 these new substances, formed out of gun cotton, 

 all are pure transparent gases, while in the case 

 of gunpowder there remain 68 per cent, of solid 

 residue, and only 32 per cent, are pure gases. 



Mechanical Applications of Gun Cotton. 

 The mechanical application of gun cotton may 

 be considered to be due exclusively to Major- 

 General Lenk, of the Austrian service. Pure 

 gun cotton becomes either a powerful explosive 

 agent, or a docile performer of mechanical 

 duty, not according to any change in its com- 

 position, or variation in its elements or their 

 proportions, but according to the mechanical 

 structure which is given to it, or the mechani- 



