THE ROYAL ARTILLERY INSTITUTION. 
19 
MONCRIEFFS PROTECTED BARBETTE SYSTEM. 
BT CAPTAIN A. MONCBIEFF, 
EDINBURGH MILITIA ARTILLERY. 
Before defining the mechanical part of this invention, it may be as 
well to state the results hoped to be obtained by it, and the principal 
difficulties that had to be encountered. 
The conditions desired were simply to obtain a system of firing over a 
solid parapet, while preserving free lateral range, and neither exposing the 
gun and detachment, nor involving the labour of raising and lowering the 
piece; in other words, of gaining the advantages of a barbette battery, 
without its defects. 
The difficulties on the other hand were mechanical ones, but mechanical 
difficulties of a very serious kind, and which I doubt not have often 
discouraged those who have been on the same track as myself; for it is 
impossible to suppose that this idea has not been entertained by many 
others. The advantages to be obtained, are too important, not to have 
often invited invention. 
It was the consciousness of this that stimulated me to persevere with my 
experiments at considerable expense, and under great discouragement, and 
delay. 
Before the end of the Crimean campaign I began to design lifts for guns, 
and in the course of this work, the principle I now adopt, occurred to me; 
as soon as it did so, I felt I had an agent suited for the purpose. 
A mechanism for raising and lowering the gun might with comparative 
ease be contrived were the strains statical, but they are very different, and 
those who know most about the difficulties of meeting the recoil of modern 
heavy ordnance on the platforms and slides now used, and the destructive 
effects large charges produce on pivots, and racers, will probably be most 
ready to appreciate the difficulty I refer to, where, as in my case, the strain 
of the recoil has not to be met near the plane of its own action, as in these 
platforms and slides, but far below it. 
The danger of the sudden strain imposed on the platform is removed by 
interposing a moving fulcrum between it and the gun, at the same time 
meeting the energy of the recoil by counterweight or some force of equivalent 
power. This arrangement reduces the initial velocity of the counterweight 
to a minimum (without destroying equilibrium). The force of the recoil is 
conveyed to the gun on the discharge taking place—the energy thus 
generated, in fact, the destructive power, is measured by the weight of the 
gun multiplied into the square of its velocity. If therefore the velocity 
conveyed to the counterweight, is at first almost disposed of, the vis inertia 
of that counterweight has no longer a destructive action on the intermediate 
parts. It is by this means alone that such enormous strains and weights 
[vol, vi.] 8 
