SHORT NOTES ON PROFESSIONAL SUBJECTS. 
131 
The escarps are strongly riveted with large blocks of stone, locally called 
cabook. It is of a deep red colour, and appears to be decomposed gneiss. It is 
soft when cut from the quarry, and hardens by exposure, but it is a tough rather 
than a hard stone. 
Owing to the nature of the ground, the breaching battery was placed at 63 yds. 
from the escarp. Some uncertainty being felt as to what the effect of the splinters 
at that distance might be, and as a space had to be levelled on the crest of the 
glacis to lay down temporary platforms for the guns, a slight parapet about 3 ft. 
thick, with embrasures for the guns, was formed of cabook. 
The work of throwing up the battery and laying down the platforms, was 
performed by Lieut. Legge, R.A., with the gun Lascars under his command. 
In laying down the battery, the crest of the glacis was levelled so as to form a 
terreplein for the guns, and, as the soil was loose and sandy, cabook stone was laid 
upon it, then broken up into small pieces, mixed with sand soaked with water, 
and well rammed until the whole formed a compact mass, with the required slope 
to the front. The cement thus formed, after being thoroughly baked by the rays 
of a tropical sun, by the following evening presented a firm and smooth floor for 
the guns. 
The practice at the escarp commenced at a quarter to five on the evening of the 
29th December, 1869. The men were kept under cover in rear of the battery until 
it was ascertained from the first few shots that no danger need be apprehended 
from splinters. The cabook being strong and tenacious, the shot penetrated it 
like a very hard cheese. The practice commenced by marking out the extent of 
the breach on each side, by shots from the right and left guns; and it was then 
intended to cut a horizontal line towards the centre from these two extreme points, 
and afterwards to cut perpendicular lines up the face; but it was soon seen that 
the number of rounds of shot was not sufficient to allow of this being done. 
Colonel Cox therefore allowed Lieut. Legge, who commanded the two left guns, 
and Captain Tweedie, who had the two right guns, each to direct their fire as 
they thought best to produce the greatest effect with the number of rounds that 
remained. The penetration of the shot was very considerable; but the great 
thickness of the walls, and the tough and tenacious nature of the material, presented 
a most formidable resistance to the effect of the shot, which had very little shattering 
effect. It is evident that cabook is well adapted for permanent fortifications. 
It is extremely durable: these escarps, built about 200 years ago, are in perfect 
preservation. It is more easily worked than stone, and splinters very little; and 
