THE ItOYAL ARTILLERY INSTITUTION. 
23l 
Hence I was compelled to adapt my designs, not as the best conceivable 
for their final object, but having regard to how they should be executed with 
rapidity, or at all. 
Were I now called upon to design a 36-inch mortar, I should not only 
modify its proportions, but greatly simplify its details, and construct its 
chase, as I first designed it, in not more than two or three thicknesses. 
And here is the place where I ought to mention how it came to pass that 
the chases of these mortars were designed in three separable segments, and 
separate from the base, and the whole of these held together by bolts. 
Before I ever put pencil to paper 1 had conversed with several friends, 
military and otherwise, as to the effect of shells of a yard in diameter on the 
forts of Sebastopol, and said I thought I could make a mortar to throw 
them that need not exceed some 30 or 40 tons weight, which I also thought 
might, without insuperable difficulties, be got to the front from Balaclava. 
All my military Engineer and Artillery friends, however, seemed to concur in 
the view that to move such a mass was out of their way at any rate, and 
that nothing heavier than say two 8-inch (smooth-bore) guns together, need 
be thought of as of any practical utility. 
Upon this I proposed to dissect the mortar—make it in pieces, none 
exceeding 10 or 11 tons—and so carry it to the front piecemeal. At every 
stage I found amongst military authorities this same view as to transport 
maintained. The result, however, was greatly, and as I am now satisfied 
most needlessly, to complicate the construction of the mortars and weaken 
their endurance. 
Now-a-days, probably, even military men would not attach so much 
importance to the difficulty of transport of heavy masses ; and for myself, I 
should, if called upon now, construct a 36-inch mortar in one permanently 
united whole, and find no difficulty in providing the means for transporting 
it over any country over which heavy siege artillery can be passed. As to 
transport by sea, of course there is no difficulty. 
There are great advantages in the form of base plate adopted, in relation 
to the mortar bed. The forward trunnion running right across the bed in 
advance of the axis, and the coin wedges right across in rear of it, well 
diffuse the powerful shock of recoil upon the material of the bed itself, and 
greatly simplify the construction of the latter. The bed, as shown in Eig. I 
of General Lefroy’s memoir, and as actually constructed, is only the top 
portion of the complete bed as designed by me; the lower portion was a sort 
of inclined slide or racer, upon which the top portion was to run between 
guides in recoil, the lower portion resting upon a level platform. Eor the 
trials at Plumstead the top portion was deemed sufficient, resting upon an 
inclined platform. This platform, as described in General Lefroy's memoir, 
proved very insufficient to withstand the component of the recoil perpendicular 
to it. The gravel became compressed and the baulks sprung into the hollow 
beneath, after the first three or four rounds. This placed the mortar at a 
great disadvantage, and unquestionably was a potential element tending to the 
fracture of the longitudinal tyebolts and cotters. 
The stress upon these bolts is not that due to the projectile force of the 
charge, but is simply that due to the mass of all parts of the mortar above 
the cup in which the shell rests. The inertia of this mass, bolts included, 
has to be overcome and motion suddenly given to it, at the velocity with 
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