210 
MR. ABEL’S RESEARCHES ON GUN-COTTON. 
Table IV. 
No. of 
experi- 
ment. 
Nature of 
material. 
Exposed 
to 
Duration 
of exposure. 
Nitrous acid 
disengaged 
after first 
exposure. 
Loss of 
weight. 
Other observations. 
91 
Ordinary gun-eotton, 
air-dry. 
100 
4 h 30“ 
20 minutes 
27 per cent.... 
The vapours were'very deep-coloured 
in 20 minutes. 
Same sample, extract- 
ed with acid. 
100 
4 h 30“ 
35 minutes 
20 per cent..... 
The vapours were not deep-coloured 
until after 2 hours’ heating. 
92 
Ordinary gun-cotton, 
quite dry. 
100 
4 h 30“ 
10 minutes 
24'4 percent... 
The vapours very deep-coloured in 15 
minutes. 
Same sample, extract- 
ed with acid. 
100 
4’> 30“ 
30 minutes 
17‘9 per cent... 
The vapours were deep-coloured after 
30 minutes’ heating. 
93 
Ordinary gun-cotton 
65 
140 hours (in 
20 days). 
30 hours, 4th 
day very 
faint. 
In one week 
1*66 per cent. 
The sample was greatly changed after 
20 days’ heating, being converted 
partly into the matter soluble in 
water, of the usual character, and 
partly into soluble gun-cotton. 
Same sample, extract- 
ed with acid. 
65 
140 hours (in 
20 days). 
38 hours (6th 
day). 
1'0 per cent... 
The sample had sustained a trifling 
change; it had contracted some-' 
what, and the soluble matter had 
increased a little. 
Upon examining the extract obtained by digesting gun-cotton with acetic acid in the 
cold, it was found to contain a small quantity of organic matter of resinous character, 
insoluble in water, but soluble in alcohol alone and in ether and alcohol, containing 
nitrogen and deflagrating when heated ; it was evident therefore that this treatment of 
gun-cotton had the effect of purifying it to some extent from the organic impurities more 
perfectly removed by the extraction with alcohol. 
The treatment of gun-cotton with dilute hydrochloric acid was not found to effect the 
removal of any proportion of these organic impurities, while the carbonates were, of 
course, readily extracted thereby. When gun-cotton, thus purified and very thoroughly 
washed, was exposed to heat side by side with the material in its original condition, 
the latter exhibited decidedly greater power of resisting change, thus furnishing an im- 
portant indication of protective power exerted by carbonates if present in gun-cotton, 
which will be presently examined into more fully. 
It is considered that the foregoing experiments afford good grounds for the following 
conclusions : — 
(1) That the invariable existence in gun-cotton of small proportions of organic im- 
purities, resulting from the partial oxidation of foreign matters enclosed within the 
cotton fibre, exerts a very prejudicial influence upon the stability of trinitrocellulose. 
(2) That there is no sound foundation for the opinion that any such influence is 
exerted by the lower cellulose-products, when associated in large or small proportions 
with trinitrocellulose. 
The following additional experimental data may be quoted in support of the latter 
conclusion : — 
A considerable quantity of perfectly soluble gun-cotton was prepared at Waltham in 
