A new expedition has been fitted out in England for the purpose of further exploring the celebrated river Niger, which is described by the Moors under the name of Net el Abeeti, or the "river of slaves," and called by the negroes, Joliba, or the "great waters." This river penetrates far into the interior of Africa, but its source may bo truly said to have never been discovered, although the lamented Mungo Park and the Brothers Landers are said to have found it. The chief obstacle to the advance of Europeans- into the inwicr of Afriea has-hitherto been the terrible climate. This has proved most deadly to the white race, and has been the great barrier to travelers anl to missionaries. When the first English expedition ascended the Niger, about 1842, so great was the mortality that on itsreturn, it is said, there were hardly enough left to throw the dead overboard. But this terrible experience did not prevent a renewal of the attempt. A dozen years later, in 1855, a second expedition sailed up the river, under Mr. McGregor Laird, who fitted out a small iron steamer for the purpose. An experienced physician who accompanied it, as soon as the steamer entered the river, began giving quinine to every man on board, in doses of about six grains. Those were given every day, and continued for sixteen weeks, or fill the time that the expedition was in the river, and was even kept up for a fortnight after it had crossed the bar again, and vvas out in the open sea. The result was that it did not lose a man ! The scourge of Africa was completely disarmed. Thus fortified against the climate, the present expedition will probably be able to prosecute its voyage in safety, mid we may reasonably anticipate great, results from its prolonged and careful explorations.