Juty 1, 1915] 
NATURE 
481 

THE USE OF COTTON FOR THE 
PRODUCTION OF EXPLOSIVES. 
HE history of the laboratory production of 
various forms of nitro-cellulose has been 
well stated by many chemists, and everything 
essential can be found either in their own 
researches or in the ordinary text-books. The 
practical outcome of such work has been the 
establishment of modes of manufacture for many 
purposes, but in the present instance it is proposed 
to deal entirely with the use of cellulose in one 
shape or another for explosives of any practicable 
kind. It is almost unnecessary to state here that 
every kind of propulsive explosive now used has 
cellulose as its basis, but it may not be super- 
fluous to say that all military propulsive explosives 
have cotton for their basis as distinct from 
cellulose. 
The word cellulose must not be understood in 
the strict chemical sense, but rather as including 
all those materials which are chiefly cellulose, and 
this definition will include materials like wood- 
pulp. Now one may clear the: ground on this 
subject at once by saying that, for military 
purposes, wood-pulp and other impure forms of 
cellulose are useless. Very good sporting powder 
can be made from nitrated wood-pulp, but the 
artillerist would be in great difficulty if he were 
provided with such a propellant, because in order 
to obtain any sort of regularity the nitration of 
the wood-pulp has to be kept at a low point, and 
the ballistics on which the artillerist depends would 
be quite thrown out. The modern gun is really 
a machine of precision; the artillerist knows that 
and expects it to throw one shot after another 
to reach the same point within a fraction of its 
possible range as computed from its elevation of 
sighting, and his whole attention has been based 
on this. If he were supplied with a material, 
however good, which on explosion developed a 
lower pressure, he would be relatively helpless 
and his rivals, using their own standard material, 
would have him at a sore disadvantage. 
In modern practice, the raw material used is 
cotton waste, which is, as its name implies, merely 
the rejected stuff in the manufacture of cotton 
goods; and although linters, which is the technical 
term for the short fibre material adhering to the 
cotton seed, may be used, yet its employment 
presents serious difficulties in that the seed with 
which it is associated has to be removed by 
chemical treatment. There have been many 
experiments made to use such substances as jute, 
ramie, kapok fibre, and in short everything from 
sulphite pulp to spun cotton, but as workable 
substances these have been rejected in favour of 
the staple material—cotton waste. 
The method of producing a satisfactory form 
of nitro-cellulose from cotton waste is as follows :— 
The waste is hand-picked so as to remove the 
grosser impurities. The product is teased, picked 
once more, and then dried. After that, the nitration 
process is carried out, and this has been much 
modified in the light of experience, but in essence 
NO. 2383, VOL. 95] 

still consists in the immersion of the purified waste 
in a mixture of nitric and sulphuric acids of the 
following composition: H,SO,, 71 per cent. ; 
HNO, 21 per cent.; H,O, 8 per cent. The 
amount of water in this mixture is important, 
and the acids as they are written are as their 
formule represent and do not refer to the com- 
mercial products. The strict relationship of 
the water to the two active materials should 
be preserved. It is of course easy now to obtain 
sulphuric anhydride (SOs) and make an anhydrous 
mixture, but this gives a nitro-cellulose with too 
high a nitrogen content. After the mixed acids 
have acted for the required time, they are removed 
and the gun-cotton is washed to remove as much 
of the acid as possible, and purified by several 
boilings with water. The boiling with water is 
of great importance, as in this part of the process 
the unstable bodies produced during nitration are 
dissolved or decomposed, leaving the  nitro- 
cellulose in a stable condition. The only thing 
now remaining is to pulp the cotton, which is 
again washed and then partly dried and moulded 
into the required shape by pressure. 
The old idea that something as nearly as 
possible to the so-called hexa-nitrate of cellulose 
should be aimed at has been fairly well exploded, 
and the manufacturer seeks to regularise his 
output so that he may obtain a_nitro-cellulose 
with approximately 11 molecules of NOs; to the 
quadruple molecule, as shown in the formula 
C3,H909(NOs),;. This formula must not, how- 
ever, be taken as any more than a convenient 
way of expressing the degree of nitration, which 
is really better stated in terms of content 
of nitrogen which ranges between 12°93 and 
13°05. This is merely a parenthesis, but is neces- 
sary as showing how delicate and complicated a 
matter it is to obtain a uniform and trustworthy 
material for propulsive explosives, and as it has 
been found in practice that even what is appar- 
ently such a simple matter as the preparation of 
a mixture of acids of known composition is really 
one requiring some care and skill. It will be 
readily understood that the difficulty is trifling 
compared with that of providing an equally regular 
form of cellulose. So well is this recognised that 
different consignments of cotton waste, all of 
approved quality, all picked, teased and re-picked, 
are mixed so that the cellulosic raw material may 
be as nearly the same grade as possible. 
With this fact in front of us, let us consider 
what the condition of a factory would be which had 
to use any kind of raw material, clean or dirty, 
lignified or not, and had to try to make that into 
a trustworthy propulsive explosive of standard 
quality. This question has only to be asked for 
the answer to provide itself. In the present case 
a great deal too much has been assumed as to 
the capability of our enemies for making trust- 
worthy nitro-cellulose without cotton waste. 
Because any competent chemist in his laboratory 
could make some form of nitro-cellulose from his 
own shirt cuffs if he pleases, people have jumped 
to the conclusion that that will be of some use 
