8 
MINUTES OF PKOCEEDINGS OF 
have also been submitted, but the Committee are of opinion that no fabric 
of this kind will equal plates of the best iron in resistance, while its splinters 
will be much more dangerous. 
14. The Superintendent, Royal Carriage Department, submitted a mantlet 
proposed by Mr Millard of that department, which is properly referable to 
the class of plate mantlets. 
It was composed of two large plates of homogeneous iron O'30 in. thick; 
the upper one suspended on a fixed joint, so as only to yield enough to allow 
the muzzle, on recoil, to clear itself; the lower one hung like a window-sash 
with counterpoises, in such a manner as to rise freely, and close the opening 
left on the recoil of the gun. As it is perfectly established that 0*30 in. iron 
will resist musket balls, the question to which the Committee have directed 
their attention has been the practical convenience of this arrangement, and 
they have to report, that there is no difficulty in working this mantlet, nor 
does it seem difficult to apply to it any masonry embrasure. Its use in any 
particular locality will depend upon the probability of its being exposed to 
artillery fire. Its advantages over shutters suspended in other ways, or 
other applications of thin iron plates, will turn chiefly on the construction 
and position of the embrasures, and appears to be rather a question for the 
Inspector-General of Fortifications than for this Committee. 
15. Captain Beaumont, Royal Engineers, has proposed a mode of pro¬ 
tecting casemated embrasures in new works by a strong shutter of 2J inch 
iron, working like a sliding door in recesses left in the masonry. This thick¬ 
ness is proof against grape-shot as well as musketry. Having recently 
reported on this plan. Report No. 1456, 23rd February 1861, the Committee 
have only to remark that it is open to the general objections raised in the 
foregoing part of this Report to iron as a material, when not capable of 
resisting cannon shot; but in other respects appears a convenient arrangement, 
especially if constructed to be raised like a portcullis into a vertical groove 
or recess, which cannot easily be choked up. Its superiority over other 
arrangements in any particular case will turn chiefly on questions of con¬ 
struction and cost. 
An Abstract of the experiments is appended. 
J. St GEORGE. 
