At 9.15 the whole army was marching south in echelon, with the rear brigade at rather more than double distance. Collinson had already started with the transport, but the field hospitals still remained in the deserted zeriba, busily packing up. The medical staff had about 150 wounded on their hands. The Sirdar's orders had been that these were to be placed on the hospital barges, and that the field hospitals were to follow the transport. But the moving of wounded men is a painful and delicate affair, and by a stupid and grievous mistake the three regular hospital barges, duly prepared for the reception of the wounded, had been towed across to the right bank. It was necessary to use three ammunition barges, which, although in no way arranged for the reception of wounded, were luckily at hand. Meanwhile time was passing, and the doctors, who worked with devoted energy, became suddenly aware that, with the exception of a few detachments from the British division and three Egyptian companies, there were no troops within half a mile, and none between them and the dark Kerreri Hills. The two gunboats which could have guarded them from the river were down stream, helping the cavalry; MacDonald with the rear brigade was out in the plain; Collinson was hurrying along the bank with his transport. They were alone and unprotected. The army and the river together formed a huge "V" pointing south. The northern extremity--the gorge of the redan, as it were--gaped open towards Kerreri; and from Kerreri there now began to come, like the first warning drops before a storm of rain, small straggling parties of Dervish cavalry. The interior of the "V" was soon actually invaded by these predatory patrols, and one troop of perhaps a score of Baggara horse watered their ponies within 300 yards of the unprotected hospitals. Behind, in the distance, the banners of an army began to re-appear. The situation was alarming. The wounded were bundled on to the barges, although, since there was no steamer to tow them, they were scarcely any safer when embarked. While some of the medical officers were thus busied, Colonel Sloggett galloped off, and, running the gauntlet of the Baggara horsemen, hurried to claim protection for the hospitals and their helpless occupants. In the midst of this excitement and confusion the wounded from the cavalry charge began to trickle in.