148 
SHOUT NOTES ON PROFESSIONAL SUBJECTS. 
In the above tables there is only one instance in which a material difference is 
shown in the pressures—viz., the first series of E.L.G. with 69 lb. shot. This powder, 
which was manufactured by Messrs. Curtis and Harvey, is decidedly of a quick 
action, and has been employed as a representative of such powders in various series 
of experiments. The velocities with the L.G. have, however, been lower in every 
series except the one in which E.L.G. powder of high density, L732, was used with 
a 691b. shot. The normal muzzle velocity in a 68-pr. cast-iron gun, with 161b. 
L.G. and service shot (which leaves a larger windage than existed in these experi¬ 
ments, and is rather lighter), is only 1579 ft. per second. It would consequently 
appear that there need be no hesitation in interchanging L.G. with E.L.G. in 
wrought-iron guns on the ground of danger to the gun, but the substitution would 
be attended with a falling off in muzzle velocity, power, and shooting qualities. 
In experimenting with the 8-inch gun, the copper cylinders by which the pres¬ 
sure is measured at the front of the cartridge have been placed occasionally in the 
same position as the Eodman knives which were employed for that purpose during 
the early stages of the Committee’s experiments ; that is to say, they were put at 
the outside surface of the gun, instead of being situated close to the bore. In all 
the five cases when this was done an enormous increase of compression resulted, as 
will be clearly seen from the following table, the differences seem to be greater 
with E.L.G. - and L.G. than with pebble powder. The results fully corroborate 
the observations on this point at p. 9 of the Preliminary Eeport, dated 5th Peb. 
1870 
i 
Pressure by crusher gauge at 
8-inch Gun. 
Muzzle 
c. 
velocity. 
A. 
B. 
Inside. 
Outside. 
1 
f.s. 
tons. 
tons. 
tons. 
tons. 
r 
1507 
ikz 
14 
16 
— 
1508 
15 
14 
_ 
27 
Pebble . 
1 
1502 
15* 
14* 
14* 
— 
1 
l 
1512 
16 
15* 
— 
26* 
1371 
29* 
25* 
20 
_ 
E.L.G. 
{ 
! 1371 
30 
22* 
— 
57 
r 
1317 
25 
18 
— 
34* 
i 
1325 
36* 
27 
21* 
_ 
L.G. 
-< 
! 
1314 
31* 
23 
19* 
— 
j 1320 
1 
30* 
22 
— 
45* 
(L.) Vi-inch M.L. Rifled Gun of 25 tons. 
One of these guns (No. 872) has been fitted with two plugs for crusher gauges 
in positions corresponding to A and JB in the 8-inch and 10-inch guns—viz., A 
through the cascable, in continuation of the axis of the bore, and B through the 
side of the powder-chamber at the centre of the charge. Pifteen rounds have been 
