The years of preparation, wasted by no one in Egypt, were employed by no department better than by the Intelligence Branch. The greatest disadvantage from which Lord Wolseley had suffered was the general ignorance of the Soudan and its peoples. The British soldiers had had to learn the details of Dervish fighting by bitter experience. But the experience, once gained, was carefully preserved. The Intelligence Branch of the Egyptian army rose under the direction of Colonel (now Sir Reginald) Wingate to an extraordinary efficiency. For ten years the history, climate, geography, and inhabitants of the Soudan were the objects of a ceaseless scrutiny. The sharp line between civilisation and savagery was drawn at Wady Halfa; but beyond that line, up the great river, within the great wall of Omdurman, into the arsenal, into the treasury, into the mosque, into the Khalifa's house itself, the spies and secret agents of the Government--disguised as traders, as warriors, or as women--worked their stealthy way. Sometimes the road by the Nile was blocked, and the messengers must toil across the deserts to Darfur, and so by a tremendous journey creep into Omdurman. At others a trader might work his way from Suakin or from the Italian settlements. But by whatever route it came, information--whispered at Halfa, catalogued at Cairo--steadily accumulated, and the diaries of the Intelligence Department grew in weight and number, until at last every important Emir was watched and located, every garrison estimated, and even the endless intrigues and brawls in Omdurman were carefully recorded.