ON THE APPLICATION OF GUN-COTTON TO WARLIKE PURPOSES, 17 
sults in the preliminary artillery experiments to be instituted with the gun- 
cotton. , 
The acids of the prescribed specific gravities were readily obtained at 
moderate prices—the sulphuric acid having a specific gravity of 1:34, and 
that of the nitric acid (a ight amber-coloured acid) being 1°52, 
The apparatus and implements employed, and the modes of conducting the 
various operations, were, as closely as practicable, in accordance with those in 
use at Hirtenberg—a slight deviation only, in the form or material of some 
of the implements, being adopted where it was decidedly advantageous and 
could not in any way influence the nature of the results. The following 
is an account of the details of manufacture :-— 
(11) a. Preparation of the Cotton.—The cotton was made up into skeins, 
those of the stout yarn weighing from four to six ounces each, and those of 
fine yarn from three to four ounces. It was then boiled for about fifteen 
minutes in a dilute solution of carbonate of potassa (of specific gravity 1-02, 
containing one pound of the salt to three gallons of water), and transferred 
thence to a centrifugal machine, which was maintained for about five mi- 
nutes at a speed of 500 to 600 revolutions per minute. The alkaline liquid 
was thus very effectually separated from the cotton, which was then washed 
thoroughly, first by hand in a large tank, and afterwards by submersion in 
a stream for forty-eight hours. At the expiration of that period, the water 
was separated from the skeins by the aid of the centrifugal machine, and the 
purified cotton was then dried: Although the cotton was of good quality and 
very fairly cleaned from seed (being quite equal in these respects to the Austrian 
samples), it was found to sustain a loss of about 5 per cent. by the treatment 
with alkali and washing. The potassa solution in which it was boiled 
acquired a coffee colour. Portions of seed were still retained by the purified 
cotton, which were subsequently dissolved out perfectly by the acids. 
(12) b. Preparation of the Acids—The proportions of acids (three parts by 
weight, or 2-45 by volume, of sulphuric acid to one part of nitric acid) were 
weighed off and transferred to stoneware barrel-shaped vessels provided with 
taps, two of these receiving the sulphuric acid and a third the nitric acid. The 
barrels were so arranged upon a suitable table that the acids could be delivered 
from the taps into a deep and very capacious stoneware vessel, fitted with an iron 
lid with suitable apertures and a tap; this vessel was raised from the ground 
sufficiently to allow of the acids being transferred from it to well-stoppered 
stoneware bottles. While the acids were flowing slowly and uniformly from 
the barrels into the covered mixing-vessel, the resulting mixture was kept 
continuously stirred by means of a large iron paddle, and after they had been 
entirely transferred (which occupied about ten minutes), the stirring was 
continued for about twenty minutes before the mixture was drawn off into 
the bottles. The product of this operation had a specific gravity of 1:82. 
The elevation of temperature resulting from the mixture of the acids was 
considerable ; in one observation the temperature of the acids before mixture 
was found to be 20° C., while that of the mixture, when complete, was 
38°C. The acid thus prepared was set aside in a cool place, and never em- 
ployed until at least twenty-four hours after the mixture had been made. 
The mixing process and all the other operations with the acids were con- 
ducted in the open air, the workmen selecting their positions with reference to 
the direction of the wind. Thus no injurious effects, nor even inconvenience, 
Were experienced by those employed. 
(13) ce. Treatment of the Cotton with the mixed Acids.—About twelve hours 
; asia in the acids, the skeins to be operated upon at one time 
; c 
