The Chemistry of Powder and Explosives - Sciencemadness Dot Org

250 NITRIC ESTERS
facture. About the same time disastrous guncotton explosions
occurred at Vinccnncs and at Le Bouchct, and these produced
such an unfavorable effect that no mure guncotton was manufactured
in England or in France for about sixteen years.
Schonbein offered his process to the Deutscher Bund for
100,000 thalers, and a committee was formed to consider the
matter, Liebig representing the state of Hesse and Baron von
Lenk, who was secretary, representing Austria. The committee
continued to sit until 1852 when it finally decided to take no
action. At the suggestion of von Lenk, Austria then acquired the
process for 30,000 gulden.
18,46. The Comptes rendus of 1846 contains several papers on
the nitration of cellulose, which papers were presented to the
French Academy before the details of Schonbein's process were
yet known. Among these, the papers by Dumas and Pelouze are
especially interesting. Dumas 82 stated that certain details of the
manufacture of guncotton had already been published in Germany.
Professor Otto of Brunswick dipped the cotton for half a
minute in concentrated fuming nitric acid, pressed between two
pieces of glass, washed until free from acid, and afterwards dried.
The explosive property can be considerably increased by
several dippings, and I have found that a product of extreme
force is obtained after an immersion of 12 hours. A point of
extreme importance is the care which ought to be exercised
in washing the cotton. The last traces of acid are very difficult
to remove, and should any remain it will be found that,
on drying, the substance smells strongly of oxides of nitrogen,
and when ignited also produces a strong acid smell. The best
test of a sample of guncotton is to ignite it upon a porcelain
plate. Should it burn slowly, leaving a residue upon the plate,
it must be considered as unsatisfactory. A good guncotton
burns very violently without leaving any residue. It is also
of very great importance that when the guncotton is withdrawn
from the acid, it should be washed immediately in a
large quantity of water. Should small quantities of water be
used it will be found that the guncotton becomes very hot,
and that spots of a blue or green color are produced, which
are very difficult to remove, and the guncotton is very impure.
Dr. Knopp of the University of Leipzig used a mixture of equal
parts of concentrated sulfuric and nitric acids, and immersed the
82 Compt. rend., 806 (1846); MacDonald, op. cit., pp. 15-17.