No. 13 battery of the left attack, armed with 13-inch mortars, had fired on the Russian works with tremendous results, but its efficiency was, in time, impaired, by the destruction of one of its platforms. It was of great moment to renew it, and corporal Borbidge and six carpenters commenced the work at four o’clock in the evening while the battery was still in action. A naval mortar required a ponderous arrangement of sleepers and planks to sustain it, for, with an ordinary charge of gunpowder, it has been known to make a vertical jump some six inches high and reach the stand again with a crushing jerk sufficient to shake the structure in every part. To meet concussions of such violence the platforms for sea-service mortars were invariably of the strongest kind. That constructed by Borbidge and his sappers—the type of many more—had, for its foundation, three transverse sleepers measuring ten inches deep and eight broad. Above them were laid, longitudinally, six beams eight inches wide and eight in depth, to which was spiked the covering consisting of massive planks nine inches in breadth and four deep. At the sides, ribands or stays of proportionate strength were bolted to the flooring, and when all was completed the platform spread over an area ten feet square. This however gives but a faint idea of the amount of labour employed in producing it. After collecting the timber—principally old joists and rafters from ruined houses—it took those seven men, using their best skill and exertions, thirteen hours to complete it! The darkness increased the difficulties of its construction, and prepared as it was under a fire of some intensity with blazing shells dropping and bursting around them, the service was advanced to the dignity of an example for future imitation. It was ready for action at five o’clock on the morning of the 18th of June. Corporal Borbidge had the reputation of being a brave man. He was the tallest sapper at the siege, approaching in height six feet four inches, and the doubled-up positions into which he was forced by the peculiar exigencies of his work, did not in the least affect a stature which was admitted to be perfect in straightness and equipoise.[186] To the French was assigned the attack on the Malakoff; to the British that on the Redan. Four columns of the latter were formed up; the first to enter the left face between the flanking batteries; the second the salient angle of the work; the third the re-entering angle formed by the face and flank; and the fourth, moving towards the Woronzoff ravine, to enter the right flank of the Redan. To each column was added a brigade of eight sappers and four carpenters laden with crowbars, sledge-hammers, grapnels, axes, and powder-bags for removing abattis, palisades, or any other obstacles which might oppose the onward dash of the stormers, and also to blow down gates and barriers.