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XI. The Bakerian Lecture. — Researches on Gun-cotton. — Second Memoir. 
On the Stability of Gun-cotton. By F. A. Abel, F.R.S., V.P.C.S. 
Received March. 19, — Read April 4, 1867. 
The earlier of the published researches into the composition and properties of gun-cotton 
were speedily followed by accounts of the spontaneous decomposition which the substance 
was, in many instances, observed to undergo upon more or less protracted exposure in 
confined spaces to strong or diffused light. These indications of instability, in conjunction 
with the occurrence of several serious explosions during the manufacture of gun-cotton 
in France and England, afforded apparently good grounds for the general conclusion, — 
arrived at within a brief period after the announcement of Schorbein’s discovery, and 
adhered to until quite recently in all countries except Austria, — that this remarkable 
explosive agent did not in itself possess the quality of uniform permanence essential to 
its safe manufacture, or to its employment with any degree of security from accident, in 
warlike or industrial operations. 
It is unnecessary to refer in detail to the results of the numerous observations pub- 
lished before 1860 upon the nature of the spontaneous changes which particular speci- 
mens of gun-cotton had suffered. In the brief prefatory review of published investigations 
upon the production and composition of gun-cotton, contained in the paper on those 
subjects which I communicated to the Royal Society last year, it has been shown that 
the products obtained by individual operators in submitting cotton to the action of 
nitric acid varied greatly in composition, and that, with only one or two exceptions, 
these could not be viewed as representing the definite substance producible by the most 
complete action at a low temperature of a mixture of the strongest nitric and sulphuric 
acids upon purified cotton-wool (or nearly pure cellulose). The behaviour and results 
of the decomposition of such specimens, or of others of more recent date prepared (for 
lectures or similar experimental purposes) without special regard being paid to their 
composition or purity, afford but little information that can be accepted as bearing upon 
the question of stability of gun-cotton when produced by a system of operation which is 
now known to furnish uniform products in a condition of comparative purity. 
There can be no question that the variations in composition of the different specimens 
of gun-cotton, the decomposition of which has received investigation at different hands, 
exerted a most important influence upon the period for which they withstood the 
destructive effects of heat and light, and upon the degree of rapidity with which chemical 
change, when once established, proceeded from stage to stage. The products of change 
described by different observers have also varied somewhat in their characters, partly 
MDCCCLXVII. 
2 c 
