But a new revelation came to Dr. Livingstone. Though the Portuguese Government had given public orders that he was to be aided in every possible way, it was evident that private instructions had come, which, unintentionally perhaps, certainly produced the opposite effects. The Portuguese who were engaged in the slave-trade were far too much devoted to it ever to encourage an enterprise that aimed at extirpating it. Indeed, it became painfully apparent to Dr. Livingstone that the effect of his opening up the Zambesi had been to afford the Portuguese traders new facilities for conducting their unhallowed traffic; and had it not been for his promise to bring back the Makololo, he would now have abandoned the Zambesi and tried the Rovuma, as a way of reaching Nyassa. His future endeavors in connection with the Rovuma receive their explanation from this unwelcome discovery. The significance of the discovery in other respects cannot fail to be seen. Hitherto Livingstone had been on friendly terms with the Portuguese Government; he could be so no longer. The remarkable kindness he had so often received from Portuguese officers and traders made it a most painful trial to break with the authorities. But there was no alternative. Livingstone's courage was equal to the occasion, though he could not but see that his new attitude to the Portuguese must give an altered aspect to his Expedition, and create difficulties that might bring it to an end. A letter to Mr. James Young, dated 22d July, near Kalosi, gives a free and familiar account of "what he was about": "This is July, 1860, and no letter from you except one written a few months after we sailed in the year of grace 1858. What you are doing I cannot divine. I am ready to believe any mortal thing except that Louis Napoleon has taken you away to make paraffin oil for the Tuileries. I don't believe that he is supreme ruler, or that he can go an inch beyond his tether. Well, as I cannot conceive what you are about, I must tell you what we are doing, and we are just trudging up the Zambesi as if there were no steam and no locomotive but shank's nag yet discovered....