300 
NEW FIELD CARRIAGE (IRON) FOR LONG-RANGE GUNS. 
The difference between the energy of recoil of the gun at the moment 
of discharge, and that of the system after that instant, expresses the 
quantity of work absorbed by the displacement of the particles of the 
trunnions and of the carriage. The difference is— 
'±iSt - Krfw. + dv (> _ +-) 
m m +m \ 2/ \m m + m ) 
= i ( m+ 
Let 
( 1 ) 
m! __ ^ _ weight of gun 
m 
weight of carriage ’ 
i ( m + f)*®* 
(1) becomes (V +1 
This last formula shows that with the same muzzle velocity the 
difference, A (work done on carriage), is less as the value of n increases; 
that is to say, the work done on the carriage is less as the relation of 
the weight of the gun to the weight of the carriage increases. 
We can, as an application of this formula, by means of the numerical 
data given above, form a table of values of A for most of the field 
carriages used, and we then find that the carriage for the 9 C Prussian 
gun is that which is strained most. The proportion of the weight of 
the gun to that of the carriage is all to the disadvantage of the latter; 
but nevertheless it stands the trial in a satisfactory manner, although 
relatively lighter than the other carriages. Its strength results from 
the substitution of steel for iron, the resistance within the limits of 
elasticity of the first-named being much greater than that of the latter. 
But steel, in spite of its precious qualities, is a very uncertain metal, 
the application of which in the construction of carriages has not yet 
been completely worked out, and upon which it is difficult to rely.* 
We can give as proof the following facts — 
In Prussia, various parts have been broken on several occasions; in 
Austria, one of the four steel carriages furnished by Krupp has had its 
trail broken. We must observe also that the 9 C Prussian gun upon its 
carriage weighs 19’3 cwt.—that is to say, 4 cwt. more than the ordinary 
Russian 4-pr. on its carriage. 
We thus see that the method of construction of existing carriages 
furnishes us with no data for the construction of a carriage at the same 
time light and fit for long-range guns; so that to solve the problem we 
are led to study a system of carriage entirely new, of which we are 
about to try to explain the chief peculiarities. We shall give later on 
a detailed description of its construction. 
In order to design a carriage, we must, first of all, make a compara- 
* The writer, of course, speaks of Russia, where this difficulty is probably a very real one*—T r. 
