As the army advanced up the valley of the Turnuk, the climate became more temperate, the harvest was later, and the troops improved in health and spirit. Concentrating his forces, Keane reached Ghuznee on July 21st. The reconnaissance he made proved that fortress occupied in force. The outposts driven in, and a close inspection made, the works were found stronger than had been represented, and its regular reduction was out of the question without the battering train which Keane had allowed himself to be persuaded into leaving behind. A wall some 70 feet high and a wet ditch in its front made mining and escalade alike impracticable. Thomson, however, noticed that the road and bridge to the Cabul gate were intact. He obtained trustworthy information that up to a recent date, while all the other gates had been built up, the Cabul gate had not been so dealt with. As he watched, a horseman was seen to enter by it. This was conclusive. The ground within 400 yards of the gate offered good artillery positions. Thomson therefore reported that although the operation was full of risk, and success if attained must cost dear, yet in the absence of a less hazardous method of reduction there offered a fair chance of success in an attempt to blow open the Cabul gate, and then carry the place by a _coup de main_. Keane was precluded from the alternative of masking the place and continuing his advance by the all but total exhaustion of his supplies, which the capture of Ghuznee would replenish, and he therefore resolved on an assault by the Cabul gate. During the 21st July the army circled round the place, and camped to the north of it on the Cabul road. The following day was spent in preparations, and in defeating an attack made on the Shah's contingent by several thousand Ghilzai tribesmen of the adjacent hill country. In the gusty darkness of the early morning of the 23d the field artillery was placed in battery on the heights opposite the northern face of the fortress. The 13th regiment was extended in skirmishing order in the gardens under the wall of this face, and a detachment of sepoys was detailed to make a false attack on the eastern face. Near the centre of the northern face was the Cabul gate, in front of which lay waiting for the signal, a storming party consisting of the light companies of the four European regiments, under command of Colonel Dennie of the 13th. The main column consisted of two European regiments and the support of a third, the whole commanded by Brigadier Sale; the native regiments constituted the reserve. All those dispositions were completed by three A.M., and, favoured by the noise of the wind and the darkness, without alarming the garrison.