132 
SHOUT NOTES ON PROFESSIONAL SUBJECTS. 
if covered with cement—as was done by the Dutch engineers—does not weather. 
There is said to be much cabook—also called laterite—on the continent of India; 
it may therefore be of importance to Engineers to know something of its capabilities 
as tested on this occasion. The fire was directed rather higher up on the escarp than 
usual, as it was necessary to fire above a line marked by the Engineers as the 
future level of the ground. 
The guns employed were one 24-pr. of 50 cwt., and three 18-prs. of 42cwt. 
The greatest penetration of shot striking the wall where the surface was not 
previously broken was— 
24-pr. 4 ft. 
18-pr. 4 ft. 2 ins. 
The depth of the breach was about 8 ft. at the apex. The greatest depth to 
’which any shot had reached was 5 ft. 7 ins. The height of the escarp was about 
38ft. The embrasures at the top of the escarp had been removed previous to 
the practice, and part of the debris shewn at the foot of the wall arose from their 
removal. The revetment was about 15 ft. thick at the place where it was partially 
breached. The total number of rounds of ammunition expended was forty-eight, 
being twelve from each gun. 
80. Demolition of No. 37 Martello Tower by Gun-cotton. May 31, 
1870. Communicated by Captain W. H. Noble, R.A. 
The Martello tower No. 37, situated on the Sussex coast between Hastings and 
Winchelsea, was selected for this experiment. 
This tower was at the time uninhabited, the upper floor and woodwork having 
been destroyed during the experiments in 1866, in connection with Gale’s protected 
gunpowder (O.S.C. Report 4258). 
The tower was similar in dimensions to those tried at Eastbourne, 1860, and 
Bexhill, 1861. It was of brick, and is said to have been built about 1803-4, at a 
cost of £3,000. The following were the principal dimensions :— 
ft. in. 
Diameter at top . 40 0 
„ foot... 46 0 
Height . 32 6 
Inside height to vault. 18 6 
Thickness, sea front. 12 6 
,, land front . 7 0 
„ over crown of vault . 5 0 
Diameter of internal central column supporting the 
vault . 4 6 
The roof of the tower was supported by a bomb-proof vault, held up in the 
centre by a pillar 4 ft. 6 in. in diameter. In appearance, the tower was perfectly 
sound, with the exception of some slight cracks in the brick-work of the central 
pillar, caused it is presumed by the heat of the previous fire. The tower was 
designed for one gun, accommodation for about twenty men, and magazine room 
for some eighty barrels of powder. Altogether, the whole structure may be said 
to have been of considerable solidity. 
The gun-cotton (200 lbs.) was arranged in three equal charges, laid without 
tamping on the basement floor, one charge being within the small magazine. The 
charges were exploded simultaneously by means of electric detonating fuzes (30 grs. 
fulminate), the firing party being at about 300 yds. from the tower. 
Looked upon as a work of demolition, the effect was very satisfactory. The 
bomb-proof roof, at the moment of explosion, appeared to rise about 2 ft. in 
the air; the walls fell outwards, as if hinged at the bottom, and the roof dropped 
