CAPTAIN NOBLE AND MR. E. A. ABEL ON FIRED GUNPOWDER. 
97 
for by the difference between the quantity of permanent gas yielded by it and by the 
other two powders. 
The corrected values of the tension, in terms of the density of the different powders, 
as indicated by the curves Plate 16, are given in the following Table: — 
Table VI. — Showing the pressure corresponding to a given density of the products of 
explosion of F. G., R. L. G., and Pebble powders, as deduced from actual observa- 
tion, in a close vessel. The pressures are given in tons per square inch, atmospheres, 
and kilogrammes per square centimetre. 
Corresponding pressures for Pebble 
and R. L. G-. powders. 
Corresponding pressures for 
F. Gr. powder. 
Mean 
density of 
products 
of explosion. 
•05 
•10 
•15 
•20 
•25 
•30 
•35 
•40 
•45 
•50 
•55 
•60 
•65 
•70 
•75 
•80 
•85 
•90 
•95 
1-00 
In tons per 
square inch. 
0 - 7 o 
1 - 47 
2 - 33 
3 - 26 
4 - 26 
5 - 33 
6 - 49 
7 - 75 
9-14 
10-69 
12-43 
14-39 
16-60 
19-09 
21-89 
25-03 
28-54 
32-46 
36-83 
41-70 
In 
atmospheres. 
107 
224 
355 
496 
649 
812 
988 
1180 
1392 
1628 
1893 
2191 
2528 
2907 
3333 
3812 
4346 
4943 
5608 
6350 
In kilos, per 
square 
centimetre. 
1102 
231-5 
367-0 
513-4 
670 9 
839-4 
1028-1 
1220-5 
1439-5 
1683-6 
1957-6 
2266-3 
2614-3 
3006 5 
3447-5 
3942-0 
4495 0 
51121 
5800-4 
6567-3 
In tons per 
square inch. 
0 - 70 
1 - 47 
2 - 33 
3 - 26 
4 - 26 
5 - 33 
6 - 49 
7 - 74 
9-10 
10-59 
12-22 
14-02 
16-04 
18-31 
20-86 
23-71 
26-88 
30-39 
34-26 
38-52 
In 
atmospheres. 
107 
224 
355 
497 
650 
812 
988 
1179 
1387 
1614 
1863 
2136 
2445 
2790 
3179 
3613 
4096 
4632 
5190 
5870 
In kilos, per 
square 
centimetre. 
110 2 
231-5 
367 0 
513-4 
670 9 
839-4 
1022 1 
1219 0 
1433-2 
1667-8 
1924-5 
2208-0 
2526-1 
2883-6 
3285-2 
3734 1 
4233-3 
4786-1 
5335-6 
6066-5 
In considering the pressures indicated, the question naturally arises as to how their 
value would be affected if the charges were greatly increased; or, to put the question 
in another form, it may be inquired whether the tensions indicated by our experi- 
ments are materially affected by the cooling influence of the vessel in which the 
explosion is conducted. 
We think there are very strong grounds for assuming that the pressure is not mate- 
rially affected by the above circumstances, except in cases where the density of the 
products of explosion is low and the quantity of powder therefore very small as com- 
pared with the space in which it is fired. 
Thus it will be observed that the pressures obtained in experiment 2 and in experi- 
ments 65, 66, and 68 compare very well (the density being about the same), although 
the quantity of powder fired in the first case is only half of that fired in the last three 
experiments. 
mdccclxxv. o 
