234 
ME. ABEL’S EESEAECHES ON GUN-COTTON. 
Experiment 151. — A long wide glass tube was loosely filled with gun-cotton. One 
extremity was drawn out to a beak which was immersed in water tinted with litmus, 
the other end was connected with a small boiler from which a rapid current of steam 
was passed over the gun-cotton, uninterruptedly, seven hours daily for three days. Not 
the slightest alteration was produced in the colour of the litmus, and the gun-cotton was 
unchanged. 
Experiment 152. — A stout glass tube, closed at one end, was partly filled with gun- 
cotton ; sufficient water was introduced to cover the latter, and the tube was then sealed 
and exposed to 100° seven hours daily for six days. When the tube was opened no 
gas escaped, the water was not acid, and the gun-cotton exhibited no signs of alteration. 
The open tube was afterwards exposed to strong daylight and sunlight ; after the lapse 
of eight months the gun-cotton was found to have a very faint acid reaction, and a 
minute trace of nitric acid was detected in the water. The proportion of matter soluble 
in ether and alcohol had very slightly increased. 
Experiment 153. — Some gun-cotton was saturated with water, which was afterwards 
expressed to such an extent that the specimen was difficultly combustible when held in 
a flame. In this condition the sample was exposed in a sealed tube to 100° seven hours 
daily for twenty-four days. When the tube was opened, no gas issued from it ; the 
gun-cotton exhibited a very faint acid reaction, but no other signs of change. The open 
tube containing the moist specimen was afterwards exposed to strong daylight and sun- 
light for six months ; the gun-cotton was then found to have a decided acid reaction. 
It was digested with a small quantity of water ; the aqueous extract was acid to test- 
paper but not to the taste ; nitric acid was detected in it, but no oxalic acid ; potassic 
hydrate imparted to it a faint yellowish tinge, and the alkaline liquid reduced cupric 
salts to a slight extent. The proportion of matter extracted by ether and alcohol was 
about double the amount originally existing in the sample. The strength of fibre was 
unaltered, and there was no appreciable diminution in the; explosiveness of the gun- 
cotton. 
Experiment 154. — 7 grms. of gun-cotton were thoroughly moistened by being sus- 
pended for some time in an atmosphere of steam ; the sample was then placed in a flask 
the sides of which were previously moistened. This flask was connected by a delivery- 
tube with another containing water, and was also fitted with a straight narrow glass 
tube. A small quantity of steam was passed into the flask from time to time as the 
moisture became partially expelled during the experiment. After three days’ exposure 
to 100° (six hours daily), a weighed sample was removed for examination. The gun- 
cotton had become slightly discoloured in a few places, where it was in immediate 
contact with the sides of the flask. Water extracted a minute quantity of colouring- 
matter; no other effect of the exposure to heat was observed. The gun-cotton was 
again heated to 100° for five days (six hours daily) ; it was then removed, the flask 
dried and weighed. By these eight days’ exposure to 100° in a moist atmosphere it had 
sustained a loss of only 1*7 per cent. A weighed sample was again examined, it fur- 
nished a very faint indication of acidity. The reactions of nitric acid could not be 
