THE HISTOEY OE EXPLOSIVE AGENTS. 
395 
were frequent increased outbursts of the flame, apparently caused by the successive fall 
of boxes from the staging into the fire beneath. When a tuft of gun-cotton wool is 
placed in a capacious vessel ( e . g. a large glass beaker) and ignited, the flash of bright 
yellow flame first observed is followed by a pale yellow lambent flame, of the character 
above described, which lasts for a distinct interval, and is due to the burning of the 
inflammable gaseous products as air enters the vessel, the slight greenish tinge being 
caused by the presence of small quantities of nitrogen-oxides. The flame observed to 
issue from the magazines was quite similar to this, and was evidently produced by the 
burning of the gases gradually developed from the wet gun-cotton. 
These last experiments demonstrate conclusively .that even very severe exposure to 
heat of large packages or heaps of distinct masses of compressed gun-cotton, saturated, 
or nearly so, with water, is not attended by risk of explosion. Just as in smaller expe- 
riments, when the proportion of water has been expelled from the surface of the heated 
gun-cotton to the extent to reduce it to about 10 per cent., those portions of the mass 
burn quietly with a weak flame accompanied by the development of inflammable gas. 
No accumulation of dry or even of nearly dry gun-cotton can consequently take place, 
and no portion of the gun-cotton can be raised to the exploding temperature. 
As compressed gun-cotton may, by employment of simple appliances, be made to 
exert its full explosive force when thoroughly saturated with water, and as it may 
therefore be applied in that condition to many of its more important uses, the non- 
liability of wet gun-cotton to explosion by simple exposure to heat, at any rate in such 
large quantities as have been experimented with, is a matter of considerable practical 
importance. The material may be easily preserved in store in an uninflammable con- 
dition, and employed at once in that state almost as readily, and with quite as much 
effect, as if it were dry; its storage in the wet state appears, moreover, to be an 
absolute safeguard against change, even when doubts exist as to the substance having 
• been thoroughly purified. Therefore, although many years must still elapse before 
general confidence in the stability of dry gun-cotton is well established, very simple 
means now exist for dealing with this material as extensively as with gunpowder, and 
with unquestionably greater safety. 
