MR. ABEL’S RESEARCHES ON GUN-COTTON. 
241 
The sides of the tube were perforated in several places, and it passed horizontally 
through the centre of the box, the openings being closed with corks. The box was painted 
black, and having been tightly filled with skeins of gun-cotton, amounting to about 
4 lbs., it was placed in the open air throughout each day in the month of August 1864, 
in a position where it would be most frequently exposed to the sun’s rays, and would 
also receive the heat radiated from a brick wall *. A registering thermometer was en- 
closed in the tube of the box, and another was placed on the outside, readings being 
taken of both twice daily. The highest temperature indicated upon the exterior of the 
box was generally about 6° or 7° above that of the centre of the gun-cotton. The tem- 
perature of the latter ranged from 14° (early in the morning) to 38°, while the tempe- 
rature-indications on the exterior of the box ranged between 15° and 47°. The average 
temperature in the centre of the box at 5 o’clock in the afternoon was 32°. At the 
close of the month the box was opened, the gun-cotton possessed the faint odour pecu- 
liar to the material when closely packed, but exhibited no signs of change. 
The box was immediately reclosed (some litmus paper being introduced) and placed in 
a chamber artificially heated. The temperature in this chamber was maintained as con- 
stantly as possible at 50°, but fluctuating a few degrees on either side. During one 
month’s exposure in this chamber the temperature of the centre was stationary at about 
49° for some time on four occasions ; but the maximum temperature attained during 
the day ranged, with those exceptions, between 43° and 47°. At the expiration of the 
month, the litmus paper was found to be reddened, and the gun-cotton had a somewhat 
pungent odour. A portion of it, extracted with a small quantity of cold water, furnished 
a very faintly acid liquid, which, upon being kept in a covered vessel for some hours, was 
found upon the following day to be distinctly alkaline. No nitric acid could be detected, 
and with the exception of the peculiar odour the gun-cotton gave no indication of 
change. It was returned to the box together with litmus paper, and exposed again to 
heat in the chamber for a few days. The litmus had then changed as before. The 
gun-cotton was now removed from the box and fully exposed to air for an hour, when 
it was repacked together with litmus paper and placed in an apartment at the ordinary 
atmospheric temperature. The contents of the box were inspected weekly ; a very trifling 
reaction was produced upon the litmus in some parts only, and this effect did not increase. 
The gun-cotton was afterwards repacked, a very imperfectly purified skein being placed 
in the centre. It was then kept in the warm chamber for seven months, during which 
period the temperature of the air surrounding the box ranged between 30° and 50°. 
When the box was afterwards opened the litmus paper was red and rotten, and the 
material possessed a pungent odour, but no nitrous vapours were perceptible. One of 
the skeins in immediate contact with the imperfectly purified gun-cotton was extracted 
with water, but furnished only a very faintly acid liquid. The box was repacked as 
quickly as possible, all apertures were perfectly closed up, and it was placed in a 
* The box was removed indoors late in the afternoon and replaced at nine in the morning. It was also 
placed under shelter when rain fell. 
