250 
ME. ABEL’S EESEAECHES ON GLTN-COTTON. 
atmosphere being only 21°) by the passage of solar heat through glass windows or roofs, 
and also stated that it was not uncommon to find the interior of powder-wagons, covered 
with metal, at a temperature of 50°-60°, while the external temperature was only 24°. 
It is evident from the nature of this statement that the elevation of temperature to this 
extent in the localities described was only transient ; but even if the atmosphere in 
magazines or ammunition-wagons were occasionally at such temperatures for several 
consecutive hours during a considerable period, it may be confidently maintained that 
gun-cotton properly purified and impregnated with a small proportion of sodic carbonate, 
as has been described, may be preserved in such localities with perfect safety, even in a 
closely packed condition. It has been shown that gun-cotton, even without the aid of 
the very decided though variable protection afforded to it by the “ silicating ” process, 
sustained no change whatever by continuous exposure to the sun’s rays in a black box 
between April and September, the temperature of the external surface of the box having 
frequently exceeded 40°, and that the same kind of gun-cotton sustained, without any 
change, three months’ exposure for several hours to an atmosphere of 50°, and did not 
exhibit any indication of change until after further exposure for nearly three months to 
an atmosphere maintained for several hours daily at 54 0- 5-55 0, 5. In both these instances 
the gun-cotton was as closely packed as possible, in one mass* (and in the latter it was 
contained in a case lined with tinned copper, which seriously influenced the effect of heat 
upon the gun-cotton). 
It is therefore considered that the extent and circumstances of exposure to heat which 
even this perfectly unprotected gun-cotton resisted, may be regarded as exceeding in 
severity such as it would have to encounter in the actual employment of the material in 
naval and military service. 
The following are some of the principal conclusions which may be drawn from the 
results of observations and investigations described in the foregoing pages : — 
1. Gun-cotton produced from properly purified cotton, according to the directions 
given by Yon Lewk, may be exposed to diffused daylight, either in open air or in closed 
vessels, for very long periods without undergoing any change. The preservation of the 
material for 3^ years under those conditions has been perfect. 
2. Long-continued exposure of the substance, in a condition of ordinary dryness, to 
strong daylight and sunlight produces a very gradual change in gun-cotton of the 
description defined above ; and the statements which have been published regarding the 
very rapid decomposition of gun-cotton when exposed to sunlight do not therefore apply 
to the nearly pure trinitrocellulose obtained by strictly following the system of manu- 
facture now adopted. 
* In ammunition-wagons, the gun-cotton would he packed in the form of cartridges, enclosed in serge, 
and with intervening air-spaces. It would therefore be in a condition much less favourable to the accumula- 
tion of heat, than the gun-cotton was, in the experimental cases. 
