86 
MINUTES OF PROCEEDINGS OF 
upon the cotton. In the immersing part of the process the water is 
highly important, for the first action of the acids upon the cotton produces 
a considerable degree of heat, but afterwards it is less necessary, for the 
cotton in the jars is not found to become seriously heated, even when no 
water is applied. The adding a fresh supply of acid after treating each 
separate quantity of cotton is found to be indispensable for securing the 
uniformity of the whole product. 
At the end of the forty-eight hours above mentioned, the cotton is taken out 
of the jars with an iron hook, attached to the centrifugal machine, and whirled 
round until the acid is so far thrown off that the skeins are only damp. 
The purification then begins, and is a highly important part of the process, 
as the safety and permanence of gun-cotton mainly depend on its being 
perfectly rid of all “ free ” acid. 
The first step is to plunge the cotton into water, agitating it in such a 
manner as will ensure that the penetration of the water throughout the fibres 
shall be immediate, for if the penetration were gradual and slow the union of 
the free acids with the water would cause a violent action of the nitric acid 
upon the cotton, and quantities of nitrous vapour would be disengaged. 
The next step is to wash it in a stream until no acid whatever is perceptible 
to the taste, and then to leave it immersed in a stream for not less 
than forty-eight hours, arranging the skeins so that the current may 
permeate freely among them. 
At the end of that period the cotton is partly dried by the centrifugal 
machine and then boiled for a few minutes in carbonate of potassa. This 
done, and the superfluous liquid thrown off by the centrifugal machine, it is 
restored to the stream, arranged as before, and left for fourteen or eighteen 
days. On final removal it is washed by hand once more, to cleanse it from 
dirt and mechanical impurities, and, after being thoroughly dried, is fully 
ready for use. 
When this process is compared with the various operations and the 
numerous machines which the manufacture of gunpowder embraces it is 
evident that the comparative simplicity attributed to the former has not been 
overstated. The ingredients of powder, after being carefully refined and 
prepared, have to be mixed, by a machine,—“incorporated” or ground 
together in another machine,—submitted to heavy pressure in a hydro¬ 
static press,—“ granulated,” in an ingenious self-feeding machine, by toothed 
gun-metal rollers ,—“ dusted ” by machinery,-—and, in the case of fine 
powders, “glazed” by producing a friction of the grains against one another. 
Moreover, some of these operations are accompanied by so much risk of 
explosion that no ingenuity or caution can entirely remove the danger, and 
not a year passes without fresh accidents being recorded. On the other hand 
the manufacture of gun-cotton, when reduced to its simplest terms, consists 
merely of a series of soakings, washings, and dryings, repeated often enough 
to ensure three things. First, that the cotton be thoroughly pure and dry 
before it is impregnated with acid; second, that every particle of cotton 
shall be well saturated with acid; and lastly, that all the free or superfluous 
acid shall be entirely removed. 
The process by which these points may be best attained is susceptible of 
some modification in its details. The system that has been described is the 
course which Mr Abel has followed at Waltham Abbey; at Hirtenberg the 
