"One of the great advantages accruing to an army on service is the close association of the officer with the man; each learns something from the other, and the officer will, in after years, appreciate the value of the habit he gets into of talking to his men and of storing up in his mind all sorts of dodges and hints, which assist troops in the field to make themselves comfortable; more than this, it is in the field only that the officer can get the opportunity of instilling into the men's minds the necessity for deliberation under fire, the high standard of the regiment, its past history, its superiority in everything to all other regiments in the division, and his confidence in his men to maintain such a standard of excellence. In many expeditions it has happened that shots have been fired at nothing, night after night, thus disturbing the whole force; such bad habits must be firmly checked." Before leaving Cairo I had the opportunity of witnessing a trial of the new siege guns that were to be used in levelling the walls and defences of Omdurman. To the eastward of Abbassieh barracks, near the rifle ranges, 150 feet of stone wall had been erected. It was a replica of part of the structure which the Khalifa had built around the tomb of the Mahdi, his own grounds, that of his body-guard, and the more important buildings situated in the centre of the dervish capital. The stout rectangular wall at Omdurman stood with its narrowest side facing the Nile, and its longest sides ran inland from the river for about a mile. It was twelve feet in height, and even more in places, ten feet in thickness at the base, tapering to six feet at the top. It was a well-made structure, laid in mortar and faced on either side with dressed limestone blocks.