Having collected his staff and supplies, he started up the Nile once more, to begin the establishment of the line of fortified posts, which he had resolved on as the best means of maintaining and extending his own authority, and at the same time of curtailing the raids of the slave-dealers. The first of these forts or stations he established at the entrance of the Saubat river, and while there he made a discovery which showed how the slave-trade flourished with such impunity. He seized some letters from a slave-dealer to the Egyptian commander at Fashoda, stating that he was bringing him the slaves he wanted for himself and many others, besides 2000 cows. By several skilful manoeuvres Gordon succeeded in rescuing all of them, restoring the cows to their owners, and compelling the soldiers of the slavehunters to return to their homes, generally in or near Khartoum. Nor was this his only success during the first two months of his government, for he detected one of his lieutenants in the act of letting a slave convoy pass in return for a bribe of £70. On this occasion he had the satisfaction of delivering 1600 human beings from slavery. This will show that one of his principal difficulties was caused by his own subordinates, who were hand-in-glove with the leading slavehunters. Another of Gordon's troubles arose from the collapse of his staff under the terrible heat. Of those enumerated as having gone up with or to him in May, all were dead or invalided in September; and the duties of sick-nurse at last became so excessive that Gordon had to order, in his own quaint manner, that no one who was sick should be allowed to come to headquarters. Only in this way was he able to obtain the time necessary for the accomplishment, single handed, of his various duties. Such was the strain on him that he gave positive injunctions that no more Europeans, and especially young English officers, were to be sent up to him. As soon as it was realised that the new Governor was in earnest, that he was bent on crushing the slave-trade, and that he would not permit corruption or extortion in any form, he became the mark of general hostility. The intrigues to mislead and discredit him were incessant. Abou Saoud, who had been formerly banished by Sir Samuel Baker from the Soudan, and then taken into high favour by Gordon, turned out a fraud and a failure, while Raouf Bey, the nominee of the Khartoum Governor-General, was sent back in disgrace. With regard to Abou Saoud it may be said that Gordon never really trusted him, that is to say he was not taken in by him, but believed he would be less able to do injury in his service than at a distance. It was precisely the same principle as led him to solicit the co-operation of Zebehr in 1884.