NEW HEED CARRIAGE (IRON) EOR RONG-RANGE GUNS. 
303 
Pressure. 
Thickness. 
Compression. 
tons 
! CWt. 
qrs. 
ins. 
ins. 
0 
0 
0 
71 
Nil 
1 
6 
0 
4-4 
2-7 
3 
16 
3 
3-84 
3-26 
5 
1 
0 
3*4 
3-7 
6 
8 
2 
3-2 
3-9 
8 
2 
2 
2-7 
4-4 
9 
19 
0 
2-48 
4-62 
13 
10 
0 
2*12 
4-98 
17 
12 
0 
1-98 
5*02 
20 
1 
0 
1-92 
5-08 
23 
10 
0 
1-84 
5-20 
30 
0 
0 
1-78 
6*32 
72 
5 
0 
1*64 
5-46 
Tlie weight of the first* of the parts into which the carriage is, so 
to speak, divided, is reduced to 3*8 cwt. It is this part, then, that on 
discharge receives the blow of the gun; then, when its own inertia is 
overcome, the motion is imparted to the second part by the inter¬ 
mediate action of the buffer, which, when firing the 9-pr. gun, with a 
muzzle velocity of 1200 f.s., suffers a compression of 1*52 ins. Table B 
(in which is given the work absorbed by the old and new carriage) 
shows that, when firing the ordinary 9-pr., the work absorbed is only 
1754 ft. lbs. by the first part (trail, &c.,) of the new carriage, while 
it rises to 3783 ft. lbs. in the old. When firing the long range 9-pr. 
with a muzzle velocity of 1200 f.s., the new carriage still only absorbs 
3529 ft. lbs., as the table also shows; from which we may conclude 
generally that the new carriage suffers much less than the old. 
To try to determine the work done by the compression of the buffer, 
we must remember that before discharge it is supporting a pressure 
of 96 cwt., as we saw above. On firing, it is further compressed 
1*52 ins.—that is to say, its thickness is reduced from 3*56 ins. to 
2’04 ins.; and the foregoing table shows that this thickness corres¬ 
ponds to a pressure of 13 tons 14 cwt. 3 qrs. nearly, which represents 
the greatest pull exercised, on discharge, by the buffer bolts. 
The work realised by the resistance of the buffer to this compression 
= mean pressure x compression 
^ 96 + 274 - 5 ^ 
112 lbs. x = 2600 ft. lbs. 
Table B shows that the carriage without a buffer absorbs 6000 ft. lbs. 
(about), while the carriage with a buffer only absorbs 3329 ft. lbs .; 
that is to say, 2470 ft. lbs. less—a difference practically equal to the 
resistance of the buffer, which, as we saw above, is 2600 ft. lbs. If it 
did not exist, the tie-bars and brackets must absorb this amount of 
work; but, thanks to the compression of the buffer, the destructive 
effects are very greatly reduced. Without it, these parts would be 
subjected to a strain very much too great; the brackets suffering* by 
compression, and the tie-bars by tension. 
* This part is of course the brackets of the trail, &c.—T k. 
