[3] Since writing the above the author has received a letter from the American Consul-general at Cairo, in which it is stated that in consequence of the insurrection in the Soudan provinces the English government has been called upon to act with Egypt in restoring the authority of the latter country. Foreseeing the great difficulties in carrying troops and stores across the Desert to Khartoum, England is seriously considering the question of a railway between Suakim, on the Red Sea, and Berber, on the Nile. In addition to its political importance, the line would have great commercial advantages, as it would afford an outlet for the rich region between Khartoum and the equatorial lakes. "Just think of it!" exclaimed Fred; "riding by railway to Central Africa, only fifteen degrees north of the equator, and in the land of elephants and crocodiles!" His meditations were brought suddenly to an end by an encounter with another string of camels, followed by several negroes, who were closely watched by a swarthy Arab, armed with a large whip. [Illustration: PROFILES OF DINKA NEGROES.] "Those men are slaves," whispered their guide; "though the Arab in charge of them would declare he knew nothing about them if you should ask him. They come from the southern country, and are of the tribe of Dinka negroes. The Dinkas are greatly liked as slaves, and bring a higher price than those from other tribes. "You see they are not tied together, or in any way restrained; but if they should try to run away they would get some sharp blows of the whip, and the Arabs that are loitering about would hinder their escape. The police would not interfere to assist either party. The slave has few friends, while all the Arabs are interested in keeping up the commerce, and are therefore the natural enemies of the captive. [Illustration: BRINGING A SLAVE TO MARKET.] "When the slave caravans are on the road the men and women are tied together, and frequently have wooden yokes around their necks, to keep them from running away. Carrying these heavy burdens, they move with difficulty, and their strength is so much exhausted that they are completely under the control of their captors." A couple of hours among the narrow streets of the old part of Khartoum, where their nostrils were constantly assailed by vile smells from the wretched drains, were quite enough for our friends, and they returned to the river bank. Their guide told them that the city was notoriously unhealthy, owing to its bad drainage. It had been fatal to a great many Europeans, and of late years the government had endeavored to remedy the evil, but had not succeeded altogether. The population is a mixed lot of Arabs, Turks, Jews, Berbers, negroes, and Europeans. The latter are principally Greeks and Italians, engaged in selling European products to the native merchants, and some of them keep small shops for vending spirits and canned edibles.