The Chemistry of Powder and Explosives - Sciencemadness Dot Org

254 NITRIC ESTERS
sideration of the users of explosives. The patent describes the
nitration of the cotton with mixed acid, the washing with running
water, the pressing, and the dipping in a very dilute solution
of potassium carbonate. "The fibre is then taken in the wet state
and converted into pulp in the same manner as is practiced by
paper-makers, by putting the fibre into a cylinder, having knives
revolving rapidly, working close to fixed knives." The patent
makes no claim to the pulping of guncotton, but only claims the
use of pulped guncotton in an explosive consisting of sodium
nitrate 65%, charcoal 16%, sulfur 16%, and guncotton pulp 3%.
1865. Abel's patent 89 for "Improvements in the Preparation
and Treatment of Guncotton" claims the pulping and the pressing
of it into sheets, discs, cylinders, and other forms and was
probably designed to cover the process of getting it into a state
where it would burn less violently in the gun. The compressed
blocks were an improvement over the yarn of von Lenk, but they
were still much too fast; they damaged the guns and were not
ballistically uniform in performance. The blocks of compressed
guncotton, however, have continued to find use in blasting. And
the outstanding advantage of Abel's pulping was that it converted
the guncotton into a state where the impurities were more
easily washed out of it, and resulted thereby in a great improvement
in stability.
1866-1867. Abel's "Researches on Guncotton" 90 demonstrated
that guncotton, after proper purification, is far more stable than
it had been thought to be. Moisture does not harm it, or exposure
to sunlight, and it decomposes only slowly at elevated temperatures
; the principal cause of its decomposition is acid, and this is
removed by the pulping. Abel wrote:
In reducing the material to a very fine state of division by
means of the ordinary beating and pulping machines, the
capillary power of the fibre is nearly destroyed, and the guncotton
is, for a considerable period, very violently agitated
in a large volume of water. It would be very difficult to
devise a more perfect cleansing process than that to which
the guncotton is submitted; and the natural result of its
application is that the material thus additionally purified
acquires considerably increased powers of resisting the de-
8» Brit. Pat. 1102 (1865); MacDonald, op. cit., pp. 45-46.
90 Loc. cit.