Their array was regular and precise, and, facing northeast, stretched for more than four miles from flank to flank. A strong detachment of the mulazemin or guard was extended in front of the centre. Ali-Wad-Helu, with his bright green flag, prolonged the line to the left; and his 5,000 warriors, chiefly of the Degheim and Kenana tribes, soon began to reach out towards the Egyptian cavalry. The centre and main force of the army was composed of the regular troops, formed in squares under Osman Sheikh-ed-Din and Osman Azrak. This great body comprised 12,000 black riflemen and about 13,000 black and Arab spearmen. In their midst rose the large, dark green flag which the Sheikh-ed-Din had adopted to annoy Ali-Wad-Helu, of whose distinctive emblem he was inordinately jealous. The Khalifa with his own bodyguard, about 2,000 strong, followed the centre. In rear of all marched Yakub with the Black Flag and 13,000 men--nearly all swordsmen and spearmen, who with those extended in front of the army constituted the guard. The right wing was formed by the brigade of the Khalifa Sherif, consisting of 2,000 Danagla tribesmen, whose principal ensign was a broad red flag. Osman Digna, with about 1,700 Hadendoa, guarded the extreme right and the flank nearest Omdurman, and his fame needed no flag. Such was the great army which now moved swiftly towards the watching squadrons; and these, pausing on the sandy ridge, pushed out a fringe of tentative patrols, as if to assure themselves that what they saw was real.