THE 110YAL ARTILLERY INSTITUTION. 
75 
The effect of this fire, concentrated upon a space of 185 square feet, has 
been to bring away nearly the whole of the granite from the exterior, except 
perhaps the two bottom courses, which being at present buried in debris, 
cannot be examined. 
No. 1132, 9*22-inch steel shell burst in the pier and blew in some of the 
brickwork and granite, leaving an opening about 18 inches by 30 inches; 
it caused a large portion of the brick backing of the pier to fall inwards or 
backwards in a mass, and produced a mass of ruin which it would be 
difficult to describe. 
The sole support of the three arches radiating from this pier appeared 
to be a narrow bearing of about two bricks on the corner of the granite 
block behind C2. 
Two salvoes were fired at the pier after this. The first was aimed about 
the level of the top of the shield, and apparently took effect there. It 
brought down an immense mass of debris, including several large granite 
blocks out of the upper course entire, and almost hid the remaining pier. 
It was getting too dark for accurate laying when the second salvo was 
fired, and from the perceptible augmentation of the opening over the east 
embrasure, it was suspected that one or two of the shot struck there. The 
others, however, struck high and about centrally, bringing down all that 
remained of E, E, and G courses, together with large blocks of concrete. 
The concrete was now fully exposed over the whole central portion of the 
work for a width of 32 feet. 
It will be impossible until the rubbish is cleared away from the outside 
and inside to ascertain minutely the state of the structure, nor is it very 
material to the issue, but it must be remembered that two or three feet of 
the base of the pier receive a support from the concrete filling in behind, 
which would be wanting in any complete structure. 
10. The granite surface of the work generally received 62 blows, to which 
are to be added 3 fired on the 18th May. Total 65. 
One of these shots did not appear to have actually struck any portion of 
the granite, but as the shock on graze was sufficient to split the block G5, 
it is counted. 
11. These blows were as follows :— 
On the two courses composing the arch over the E embrasure, 12, viz.:—- 
yds. 
foot tons. 
7"*0 cast-iron shot . 
. 600 
2 
2994 
S"-0 „ . 
. 1000 
2 
3472 
9"-22 „ . 
. 1000 
3 
7998 
9"*22 . . 
. 600 
1 
2969 
10"‘0 steel shot 
. 600 
1 
3146 
10"-0 cast-iron shot .. 
. 1000 
3 
8514 
29,093 
Average blow ... 
...2424 
