310 NEW FIELD CARRIAGE (IRON) FOR LONG-RANGE GUNS. 
Results to be Obtained by the Introduction of such Carriages. 
Let us now enquire what would be the theoretical gain resulting 
from the introduction of such carriages in our own service, in con¬ 
junction with the new experimental 7-cwt. field gun. 
We suppose the gun to weigh 7 cwt., about (800 lbs.), and the whole 
carriage to be 10’5 cwt. (1200 lbs.), and to fire a 15-lb. shell with a 
muzzle velocity of 1550 f.s. A glance at the following table would 
show what an extremely powerful gun we should possess. 
The velocities are compared with those of the present 16-pr. at 
similar ranges. Approximately we have 
Gun. 
Weight. 
Charge. 
Calibre. 
Muzzle 
velocity. 
Energy. 
cwt. 
lbs. 
ins. 
f.s. 
ft. tons. 
16-pr. 
12 
3 
3-6 
1350 
203 
15-pr. 
7 
about 3| to 4 
3-0 
1550 
251 
Velocities mid Energy. 
Muzzle. 
1000 yds. 
2000 yds. 
3000 yds. 
4000 yds. 
f Velocity, f.s. 
1350 
1010 
867 
763 
682 
16-pr. 4 
(.Energy, ft. tons... 
203 
114 
83 
65 
51 
(■Velocity, f.s. 
1550 
1201 
993 
890 
804 
15-pr. ] 
(. Energy, ft. tons... 
251 
150 
104 
82*5 
67 
Gravity = g = 32 f.s. 
On referring to table B, in which the results are obtained by the for¬ 
mula given above, we find that the gun has a velocity of recoil = 33 ft., 
and that the energy of recoil = 13,600 ft. lbs. 
We also see that the energy of recoil of gun and carriage together 
== 5280 ft. lbs., leaving no less than (13,600 — 5280) = 8320 ft. lbs. as 
the work expended on the material of the carriage. 
This is a much higher strain than is borne by any continental carriage, 
as may be seen by reference to table A. 
Suppose, however, we divide the carriage into two parts, in a similar 
manner to that above described. The first part is supposed to weigh 
4 cwt. (Russian iron one only weighs 3’87 cwt.) The total weight 
of gun and first part, then, = 800 + 450 = 1250 lbs. 
Calculating as above, we find that the energy of recoil = 8590 ft. lbs., 
and that consequently only 5010 ft. lbs. are absorbed by the material 
of the carriage. On the ordinary form, as we saw, 8320 ft. lbs. were 
absorbed. Thus we have a difference in favour of the new method of 
8320 -5010 = 3310 ft. lbs. 
Let us proceed, then, to calculate what work is done in compressing 
