ME. ABEL’S EESEAECHES ON GUN-COTTON. 
197 
gun-cotton was determined at intervals ( e . g. at the close of six hours, or one day’s ex- 
posure to heat), the nitrous acid contained in the vessel being first displaced. 
The vessels employed in these experiments were globe-flasks fitted by means of per- 
forated corks, with long narrow glass tubes, and in most instances with thermometers 
graduated from 100° C. upwards. The flasks were of a size to receive the gun-cotton in 
a compact condition, and the thermometer-bulbs were inserted into the 1 centre of the 
mass. Continuous observations were made in safety during the experiments, through a 
small glass let into a wooden screen, which was placed in front of the water-bath con- 
taining the heated flask. The results obtained are tabulated for convenience of com- 
parison. 
Table I. 
Description of 
gun-cotton. 
Quan- 
tity 
em- 
ployed. 
Total expo- 
sure to 100° C. 
Interval be- 
tween first ex- 
posure to 1 00° 
C., and first 
signs of de- 
composition. 
Loss of weight 
sustained by 
the gun- 
cotton. 
Temperature observations. 
Other observations. 
Coarse yarn made 
in 1864, Wal- 
tham. 
grms. 
1GOO 
20 hours (in 
4 days). 
4 hours 
1 per ct. in 6 h , 
12- 91 per ct. 
in 12" 30 m . 
13- 91 p.c.= 
total loss in 
18 hours. 
Not made in this experiment 
The gun-cotton exploded violently 
soon after commencement of the 
4th day’s heating. Nitrous acid 
was copiously evolved just before 
the explosion. 
Coarse yarn, Wal- 
tham. 
22 
5 h 30 m (30 
minutes on 
the second 
day). 
2 hours 
8 35 per cent, 
in 5 hours. 
The thermometer remained almost 
stationary during the first 41 
hours. It then rose continuously 
and reached to 109° C. in 25 mi- 
nutes, when the experiment was 
interrupted. On 2nd day, when 
the thermometer reached 100° C., 
it continued to rise; within 30 
minutes it indicated 122° C., and 
the gun-cotton exploded very 
shortly afterwards. 
The evolution of nitrous acid, when 
it once commenced, continued 
copious throughout the experi- 
ment. The explosion of the gun- 
cotton was very violent. 
Coarse yarn, Wal- 
tham. 
6-5 
24 hours (in 
4 days). 
8 hours 
23 -7 per cent, 
in 24 hours. 
The thermometer did not rise above 
100° C. on the first day. On the 
2nd day, after 1 j hour’s heating, it 
rose slowly till it reached 109° C. 
It remained nearly stationary at 
that point for 1| hour, and then 
gradually fell to 100° C. towards 
the close of the 2nd day. No rise 
of temperature was observed on 
the 3rd and 4th days. 
At the conclusion of the experiment 
the sample had contracted some- 
what, and assumed a brown co- 
lour. It was quite friable, and 
had lost the properties of gun- 
cotton. 
Eine yarn, Wal- 
tham. 
6*5 
21 hours (in 
3 days). 
3 hours 
30 per cent. in| 
21 hours. 
A slight increase of temperature was 
indicated at the close of the 3rd 
horn-, the highest temperature, 
110° C., being indicated 3 U 5U m 
after commencing the experiment. 
Shortly afterwards the thermo- 
meter began to fall ; after the 
lapse of 1 hour it indicated 103° 
C., and had fallen to 100°C. before 
the close of the 1st day. No rise 
in temperature was observed on 
the 2nd or 3rd days. 
The gun-cotton began to darken on 
the 2nd day. At conclusion of 
experiment it had contracted 
considerably, was dark brown, 
yielded a considerable proportion 
to water, in which the usual pro- 
ducts of change were detected. 
The residue was nearly soluble in 
alcohol, and completely so in 
ether and alcohol. 
Coarse yarn from 
Hirtenberg. 
6-5 
33 minutes . . . 
20 minutes ... 
The thermometer began to rise 25 
minutes after first exposure, and 
continued to do so very rapidly 
up to the time of explosion. 
The gun-cotton exploded violently 
after 33 minutes’ exposure to 100° 
C. 
Coarse yarn from 
Austria (another 
specimen). 
6-5 
1 hour 
15 minutes .. , 
The thermometer began to rise 45 
minutes after first exposure, and 
continued to rise rapidly, indi- 
cating 129° shortly before the ex- 
plosion. 
The gun-cotton exploded violently 
after exposure to 100° C. for one 
hour. 
mdccclxvii. 2 E 
