THE 80-TON GUN. 
467 
breech-loading than with muzzle-loading guns. Table B indicates 
pretty clearly that in the German experiments the density of about 
35 cub. ins. to the pound of charge gave the best results in the gun of 
56 tons. The most suitable air . space for our service guns is not yet 
accurately known, but it appears fairly certain that the larger the 
calibre the less should be the density of the charge; because, as the 
weight of the projectile increases approximately with the cube of the 
diameter, while the surface of its base, exposed to the driving action of 
the gas, increases only as the square, greater pressure per square inch 
is required bo set the bigger shot in motion, and it will move more 
slowly away, and will give more time for the density of the expanding 
gas behind it to increase. 
TABLE B. 
Krupp B.Lo 33*5 C (13*97 Q-in.) Gun. 
Experiments at Krupp’s works, 27.12. 75. 
6 
bS) 
g 
Space occupied by charge. 
*8 
Energy. 
c8 
¥ 
T3 
a 
Description of 
o 
a . 
*3 
Volume. 
g § 
1 
% 
3 
powder. 
o 
§3 
^4 (D 
S> 
© 
O 
« 
;§> 
4' 
rg 
b d 
<D 
1 
*3 
& | . 
u 
Q 
N 
N 
% 
m 
m 
o 
.a 
n 
S 
§ 
1-4 
ft 
'o 
tS o-S 
rt 
H 
1 
"o 
H 
Pn 
lb. 
lb. 
ins. 
ins. 
c. ins. 
c. ins. 
ft.tons 
ft. 
tons. 
ft.tons 
ft.tons 
1 
Ordinary prismatic 
Prismatic powder'') 
176-4 
1157-4 
59-568 
14-449 
9767 
55-37 
553 
1209 
21-2 
11727 
267-1 
2 ) 
with one hole, / 
100 prisms weigh- C 
ing 8'377lbs. ) 
220-46 
1155-2 
59-213 
14-449 
9709 
44-04 
853 
1360 
17*4 
14833 
337-8 
3 
n n 
242-5 
1147*5 
59-017 
14-449 
9677 
39-90 
923 
1445 
18-0 
16609 
378 
4 
n ii 
264-5 
1145-3 
58-978 
14-449 
9671 
36-56 
? 
1517 
P 
18270 
416 
5 
n n 
275-6 
1143-1 
59-686 
14-449 
9787 
35-51 
794 
1567 
24-5 
19457 
443 
6 
n a 
275-6 
1139-8 
59-174 
14-449 
9703 
35-20 
841 
1565 
23-0 
19351 
441 
7 
a „ 
275-6 
1145-3 
58-663 
14-449 
9619 
34-90 
874 
1567 
22-3 
19494 
444 
8 
ii a 
286-6 
1146-4 
59-017 
14-449 
9677 
33-76 
802 
1595 
25-2 
20217 
460 
9 
If II 
297 6 
1146-4 
59-370 
14-449 
9735 
32-71 
822 
1637 
25-9 
21295 
485 
10 { 
Large grain from! 
•984 to 1-181 in... J 
297 6 
1145-3 
59-489 
14-449 
9755 
32-77 
965 
1390 
15-9 
15340 
349 
After two or three preliminary rounds, the Committee on Explosives 
decided to fix upon 30 cub. ins. as the standard, and proceeded to 
carry out the next experiment with the gun in its 15-in. calibre on this 
basis. 
Table C gives the particulars of the rounds fired under these new 
conditions. 
The rounds are arranged in such order as to show clearly the series 
fired with each size of powder. As long as the usual method of 
ramming the shot and cartridge hard home was adhered to, the best 
result* had been obtained in round 9, when 2201b. of 1’5-in. powder 
yielded nearly 21,000 ft. tons of energy with the moderate mean pres¬ 
sure of 23*3 tons behind the shot, while the maximum did not exceed 
24*5 tons. The highest result had been given at round 3 by 230 lb. 
of 1'7-in. powder, when nearly 22,000 ft. tons of energy had been 
achieved; at the expense, however, of a mean pressure of 26*2 tons, 
the maximum reaching 27*6 tons per square inch—a pressure which 
artillerists consider too high for continuous firing and for the various 
* able A, 
