THE ROYAL ARTILLERY IHSTITTJTIOF. 
879 
affected,, and tlie result may be actual combustion. This occurs not only to 
cotton, but linen rags, as well as to sawdust and many other organic 
substances. The conditions affecting Lenk's gun cotton are almost 
diametrically opposed to the preceding. Firstly, the three easily removable 
atoms of hydrogen present in ordinary cotton are disposed of by what may 
be called azotization; then the long process of acid-steeping involved oxidizes 
everything in the cotton that can be azotized; whence it follows that there 
remains nothing for atmospheric oxygen to act upon. Finally, slow decay, 
or “ eremacausisf to which ordinary cotton is subject, cannot affect Lenk’s 
gun cotton. 
Granting that atmospheric oxygen has no influence, still the theoretical 
allegation may be adduced that oxygen of water is not without influence. 
But the Hirtenberg gun cotton lies for several weeks in water; moreover, 
is finally boiled with weak potash solution. Now, if it be easily changeable 
by water, it must surely have changed under this treatment: nevertheless, 
every analysis demonstrates the result to be tri-nitro cellulose. It may still 
be argued, that if oxygen and atmospheric moisture do not produce material 
changes, still summer heat would do so ; but examples such as the black 
cases which have lain for months in the open air on railway stations, exposed 
to the direct action of the sun, and the specimen already referred to, where 
more than one pound of gun cotton was exposed for more than four weeks 
to the direct action of the sun towards the south in all weathers, retaining 
still its full explosive properties, demonstrate a sufficient explosive constancy. 
If, however, gun cotton be prepared otherwise than as in Hirtenberg—or if 
not prepared in Hirtenberg, according to the special instructions of General 
von Lenk (of which, until now, no example was before us)—then, no doubt, 
there might be risk of combustion as in the case of the French cotton. 
[With regard to these “ theoretical proofs,” it is much to be desired that their practical soundness 
be tested thoroughly by searching experiments upon a sufficient scale]. 
How the Explosion of the French Cottons are to be accounted for. 
15. The explosion can be accounted for in the following way : indeed, 
it has been mostly explained already. 
If the acids are not strong enough, or not permitted to act sufficiently long ; 
if, moreover, the subsequent removal and neutralization of acid be not 
complete, so that free acids remain; then the atoms of unremoved hydrogen 
may become the focus of chemical energy, which rising to a sufficient degree 
of intensity, may result in explosion. 
To effect the perfect azotization by and contact in the first place, which 
the case requires, and to separate or neutralize every lingering trace of in 
the second place, demand time and attention to detail. We may with 
confidence affirm that French gun cotton differed from that of Lenk. From 
considerations based upon grounds already stated, it probably was not 
without traces of free acid. 
It now remains, lastly, for us to enquire into the so-called disruptive 
explosibility (vis viva, oy force brisante ) of gun cotton. 
