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MINUTES OF PROCEEDINGS OE 
attended by a considerable evolution of heat. Hence, the detection of acid, generated in gun cotton, 
which was originally quite neutral, is a very different matter from the discovery of a minute 
quantity of sulphuric acid in gunpowder ; the latter cannot affect the stability of the gunpowder, 
while the former may be an indication of changes, not only destructive to the gun cotton, but 
productive of heat, sufficient, by its accumulation, to lead to the ignition of the material]. 
These observations are only intended to show that no great importance 
should be attached to the casual reddening of litmus paper by gun cotton. 
Parity of reasoning should lead to the rejection of gunpowder : and, indeed, 
gunpowder by long exposure to atmospheric influences is so deteriorated as 
to be rendered wholly unfit for ballistic uses. 
[This last assertion is certainly not warranted by our knowledge of the nature and properties of 
the two materials. The deterioration of gunpowder by exposure to atmospheric influences is well 
known to be due solely to the absorption of moisture by it. The remarks made on some of the 
statements under the preceding heading, bear likewise upon this statement]. 
Temperature at which Gun Cotton Ignites . 
10. The rejection of gun cotton, in consequence of the changeable 
nature of, or the explosive quality of the material at low temperatures of 
the material, is so thoroughly and decidedly contradicted in the Report of 
Baron von Ebner, that it would be superfluous to go any further into this 
question; the lowest explosive temperature of the Hirtenberg gun cotton 
being therein fixed at 136°; a temperature which, practically, cannot raise 
any doubts against the use of gun cotton. 
Gunpowder and Gun Cotton compared as to Temperature of Ignition. 
11. Nevertheless, it is of interest to introduce something regarding the 
qualities of gunpowder. Mixed with sulphur, charcoal ignites at a lower 
temperature than by itself. A mixture of sulphur with charcoal, that had 
been prepared at temperatures between 150° and 400° C., begins to ignite 
at 250°; whereas a mixture of sulphur with charcoal, resulting from a 
temperature between 1000° and 1500°, when heated to 250° only burns off 
the sulphur, without the combustion of the charcoal. 
Charcoal decomposes saltpetre at a temperature altogether different from 
the degree of heat at which charcoal is produced. Charcoal prepared 
at temperatures between 150° and 430° decomposes saltpetre at 400°. 
Charcoal prepared between 1000° and 1800° decomposes saltpetre at a 
dark-red glow heat. 
Sulphur decomposes saltpetre at higher temperatures than the charcoal, 
namely, at about or over 432°. The temperature at which sulphur burns 
in the air is, according to Yiolette, 250°, and at this temperature gunpowder 
also explodes. The explosive quality of various sorts of gunpowder is 
different, according to the sort of charcoal used, the proportions of the 
mixtures, and the size and compactness of the grains. Yiolette observes, 
that an exact knowledge of the alterations in the composition of the charcoal 
of powder, in proportion to the temperature of the charcoaling process, 
must be followed by changes in the respective proportions in the mixture 
