122 CAPTAIN NOBLE AND MR. E. A. ABEL ON EIRED GUNPOWDER. 
open air to be about 2 seconds. The same sample was entirely consumed in the bore 
of a 10-inch gun, and must therefore have been burned, in less than '009 second. 
T. EEPECT OP MOISTURE UPON THE COMBUSTION AND TENSION OF POWDER. 
It is perhaps unnecessary to say that we do not share the views of those who 
consider that the presence of water in powder may increase the tension of the products 
of explosion. We have made no experiments upon this head in closed vessels ; but the 
following Table exhibits the effect of moisture in gunpowder upon the velocity of the 
projectile and the tension of the gas when the powder is fired in a gun, the proportions 
of moisture varying from 0 - 7 to T55 per cent. The powder from which these results 
were obtained, was pebble, carefully prepared by Colonel Younghusband, and was the 
same in all respects, except as regards the quantity of moisture. 
Table XV. — Showing the effect of moisture in the powder upon the velocity of the 
projectile and pressure of the gas. 
Percentage 
of 
moisture. 
Velocity. 
Maximum Pressures. 
feet. 
metres. 
tons per 
square inch. 
atmospheres. 
070 
1545 
470*92 
22-02 
3353 
075 
1541 
774-50 
21-70 
3304 
0-80 
1537 
468-47 
21-38 
3256 
0‘85 
1533 5 
467-41 
21-07 
3208 
0-90 
1530 
466-34 
20-77 
3163 
0-95 
1526 5 
465-30 
20-47 
3117 
1-00 
1523-5 
464-40 
20-18 
3073 
1-05 
1520 5 
463 44 
19-90 
3030 
1-10 
15175 
462 53 
19-63 
2989 
1*15 
15145 
461-61 
19-37 
2949 
1-20 
1512 
460-85 
19-12 
2911 
1-25 
1509-5 
460-10 
18-87 
2873 
1-30 
1507 
459-33 
18-63 
2837 
1-35 
1504-5 
458-60 
18-40 
2802 
1-40 
1502 
457-80 
18-18 
2768 
1-45 
1499-5 
457-04 
17*97 
2736 
1-50 
1497-5 
456-43 
1776 
2704 
1-55 
1495-5 
455-82 
17-55 
2672 
From this Table it will be seen that by the addition of considerably less than 1 per 
cent, of moisture, the muzzle-velocity is reduced by about 60 feet, and the maximum 
pressure by about 20 per cent., pointing obviously to a much more rapid combustion 
in the case of the drier powder. 
U. LOSS OF HEAT BY COMMUNICATION TO THE ENVELOPE IN WHICH THE CHARGE 
IS EXPLODED. 
We have now given a hasty sketch of the means that have been adopted to determine 
the pressures actually existing in the bores of guns, and of the general results we have 
