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MINUTES OF PROCEEDINGS OF 
(5) As to the true position of the interior cavity, according to specifi¬ 
cation. The failure of many of the 24-inch cast-iron shells fired at the 
siege of Antwerp suggested a doubt to some officers whether that material 
could be trusted for 36-inch shells; and to meet this objection, a plan 
was devised for casting them over wrought-iron cores, made of two 
hemispheres, rivetted to a flat ring; the lower half was to have been of 
0*5 in. iron, the upper of 0*25 in. This intention was, however, abandoned, 
and they were made wholly of cast-iron; but the core was placed in the 
mould so as to give a greater thickness at the bottom of the shell than at 
the fuze hole. The latter dimension was 2*0 ins., the former was about 
5*0 ins. in the heaviest, and 4*6ins. in the lightest shells; and at 30 cubic 
inches to one pound of powder, their internal capacities would have varied 
between 405 and 487 lbs. Mr. Mallet calculated to throw a bursting charge 
of 480 lbs. If we suppose that the sand and sawdust with which they were 
filled set up or consolidated as much as gunpowder does, we shall have a 
degree of eccentricity of the shells when fired which must have materially 
influenced their flight.* 
11. The following extracts from a letter of Mr. Mallet's, dated 2nd May, 
1857, will explain some of the difficulties attending the actual completion of 
the contract:— 
“ I submit the following resume of that part of my own views which refers to 
mode of delivery, and of the primary trials, &c.:— 
tc (1) Each of these mortars weighs about 40 tons; the heaviest pieces upwards 
of 12 tons. 
“ (2) They will require strong and peculiar tackle to put them together, and 
they will be endangered if attempted being put together by even skilled persons, 
if not familiar with their construction. The same applies to taking asunder. 
“ (3) They will require a firm foundation or platform to be made to put them 
together upon, wherever done. 
“ (4) The shells (50) and the two cranes for loading them into the mortars are 
all now at Woolwich.f 
“ (5) The contractor for the mortars is bound to deliver and put them together 
once at Woolwich Arsenal, but only once. Subsequent taking asunder will cost a 
considerable sum. 
* The centre of gravity of the empty shell would be 1-5 in. from the centre of the outer sphere, 
and the compression of the bursting charge on firing the mortar would add to this eccentricity 
about 0-2in,; so that the centre of gravity of the shell when fired would be as much as 1*7in, 
distant from the centre of the sphere. 
f The cranes were supplied by Messrs. Fox, Henderson & Co., at a cost of £150 each. 
