The massive wall on the south and west faces was twenty feet high, covered at a distance of thirty feet by a lower wall fifteen feet high; the southern wall was pierced at intervals of about 700 yards by gateways, three in number, protected by lofty circular bastions, and between these and at the four corners were a series of low bastions which gave an admirable flanking fire.  The wall on the western flank was of similar construction, but had been considerably damaged at the northern end, evidently by an explosion of gunpowder.

The weak part of our defence was on the eastern face, where the wall, which had never been completed, was only seven feet high, and did not extend for more than 700 yards from the south-east corner; the line then ran to the north-west, and, skirting the village of Bimaru, ended at the foot of the ridge.

From this description it will be seen that, though the perimeter[1] of Sherpur was rather too large for a force of 7,000 effective men to defend, its powers of resistance, both natural and artificial, were considerable.  It was absolutely necessary to hold the Bimaru ridge for its entire length; to have given up any part of it would have been to repeat the mistake which proved so disastrous to Elphinstone’s army in 1841.  In fact, the Bimaru heights were at once the strength and the weakness of the position.  So long as we could hold the heights we were safe from attack from the north; but if we had been forced, either from the weakness of our own garrison, or from any other cause, to relinquish the command of this natural barrier, the whole of the cantonment must have lain open to the enemy, and must forthwith have become untenable.

The question of how Sherpur could best be defended had been carefully considered by a committee,[2] assembled by my orders soon after our arrival in Kabul; and a scheme had been drawn up detailing the measures which should be adopted in case of attack.

On the recommendation of this committee six towers had been constructed on the Bimaru heights, and shelter trenches and gunpits made at the points where Infantry and Artillery fire could be used with the greatest advantage.  These trenches were now deepened and prolonged, so as to form one continuous line of defence, protected by an abattis; and the defences in the depression between the heights were so arranged that fire could be brought to bear on an enemy advancing from the north.  To strengthen the north-east corner, a battery was thrown up on the slope of the ridge, which was connected with the tower above and the village below.  The village itself was loop-holed, the outlying buildings to the front made defensible, and the open space to the north-east secured by abattis and wire entanglements.  The Native Field Hospital was strengthened in like manner, and sand-bag parapets were piled upon the roof, which was somewhat exposed.