But while the attention of the Khalifa was directed to these matters, a far more serious menace offered from another quarter. Unnoticed by the Dervishes, or, if noticed, unappreciated, the railway was stretching farther and farther into the desert. By the middle of July it had reached the 130th mile, and, as is related in the last chapter, work had to be suspended until Abu Hamed was in the hands of the Egyptian forces. The Nile was rising fast. Very soon steamers would be able to pass the Fourth Cataract. It should have been evident that the next movement in the advance of the 'Turks' impended. The Khalifa seems, indeed, to have understood that the rise of the river increased his peril, for throughout July he continued to send orders to the Emir in Berber--Yunes--that he should advance into the Monassir district, harry such villages as existed, and obstruct the frequent reconnaissances from Merawi. Yunes, however, preferred to do otherwise, and remained on the left bank opposite Berber until, at length, his master recalled him to Omdurman to explain his conduct. Meanwhile, determined with mathematical exactness by the rise of the Nile and progress of the railway, the moment of the Egyptian advance arrived. At the end of July preparations were made, as secretly as possible, to despatch a flying column against Abu Hamed. The Dervish garrison, under Mohammed-ez-Zein, was not believed to exceed 600 men, but in order that there should be no doubt as to the result it was determined to employ a strong force. A brigade of all arms was formed as follows:-- Commanding: MAJOR-GENERAL HUNTER Cavalry....... One troop Artillery ...... No. 2 Field Battery [This battery consisted of six Krupp guns, two Maxims, one Gardner gun, and one Nordenfeldt--an effective medley.] Infantry....... MACDONALD'S BRIGADE --3rd Egyptian --IXth Soudanese --Xth " --XIth "