MINUTES OF PROCEEDINGS OF 
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that opposite the ditch of a ravelin, which it is impossible entirely to screen 
against a besieger's curved fire, might however be desirable. Without using 
iron much may doubtless be done to render walls less easily breached than 
heretofore, by the more general use of counter-arched revetments. Captain 
Scott, R.E., suggests the construction of these entirely of cement concrete in 
the manner shewn in Yob XI. “K. E. Professional Papers," p. 238; where the 
gravel and lime are abundant on the spot, an escarp of this kind can be built 
at a cost of about half the price of an ordinary revetment of brickwork of the 
same height. It is the opinion of Captain Eowke, who has had great success in 
concrete constructions, that from the peculiarity of concrete, it being as it were 
monolithic, it is peculiarly adapted for the construction of escarps, as in the 
event of a large part of the front of an escarp being breached, it is by no 
means certain to bring down the superincumbent mass of the wall. Sir John 
Burgoyne is also of opinion that concrete forms so connected a mass, that it 
will bear great openings without the upper mass falling. It seems therefore 
most desirable that experiments should be carried on against concrete walls 
with a view to ascertain their powers of resisting breaching, as in the only 
ones recorded, viz. against a bomb proof in the Marshes in 1835, and 
against a wall in the United States in 1854, the concrete had not been given 
time to dry properly, and was not compounded of the most suitable lime. 
While speaking of concrete, it may be mentioned that at these same expe¬ 
riments in the United States, blocks of lead concrete (formed by pouring 
molten lead into moulds nearly filled with heated fragments of brick and 
stone), were used in the construction of casemate embrasures, and were found 
to offer great resistance to the fire of heavy guns at short ranges. Colonel 
Totten reported that heavy balls with high velocities penetrated into it little 
more than, their diameters, moulding for themselves a symmetrical bed, in 
which they were found crushed. They caused no cracks through the mass, 
and detached only very small and harmless splinters. He considered that 
next to wrought iron, it was out of a great number of substances experi¬ 
mented on, the best. Similarly favourable results having I believe been 
arrived at in some recent experiments at Copenhagen, lead concrete would 
seem well worthy of a trial either as a substitute for, or in combination with, 
wrought-iron in casemate embrasures. 
The remarks that have been already made will of course apply both to the 
works forming a continued enceinte, or to detached works. With regard 
to these latter, it is perhaps hardly necessary to observe that they must, if 
intended to protect a dockyard or arsenal from bombardment, be advanced 
much more than was formerly considered necessary, while their distance from 
each other may be increased. Those now under construction or considera¬ 
tion according to the plan drawn up by the Defence Commission, vary for 
example in distance from the works they are intended to protect, from 2000 
to 9000 yds. Their general outline is more or less that of flat lunettes, the 
gorges being occupied by casemated keeps. The drawings before you shew 
the general arrangements of one of these works. It will be observed that 
the flanking of the ditch is obtained principally by caponiers; and it is 
conceived that one result arising from the improvements in artillery will be 
the adoption of the polygonal trace in preference to the bastioned for the 
important fronts of works, owing to the far greater facility of tracing the 
work, so that the faces and caponiers may be protected from distant enfilade 
