The French are going to send a new Scientific Exploring Expedition to South America, chiefly for researches in Brazil and Paraguay. Perhaps the veteran Bonpland, who was so long detained by the dictator Francia, may be induced to come home in it, as he has written to express his desire of returning to France. And something has been said at Washington, about sending a couple of frigates to survey the great river Amazon, in which, as the official document states, there is a sufficient depth of water to float a large ship at the foot of the Andes, 1500 miles from the sea. America will surely be well known some day. Meanwhile, we are extending our knowledge of Africa; a map of that country is about to be published, comprising the whole region from the equator to 19 degrees of south latitude. In this the recent discoveries will be laid down, and we shall see Mr Galton's route of 1600 miles from Walfish Bay to Odonga, near a large river named the Nourse, and to the country of the Ovampo, described as an intelligent tribe of natives. We shall find also, that the snow-peaked mountains seen by the German missionaries, and considered to be the source of the White Nile, are not more than about 300 miles distant from the eastern coast; and it is said that no more promising enterprise could be undertaken, than an attempt to ascend and explore them, starting from Mombas. Barth and Overweg were at the eastern end of Lake Tchad when last heard from; and we are told that the slave-traders, finding their occupation decreasing on the western coast, have lately, for the first time, penetrated to the interior, and tempted many of the natives to sell their children for showy European goods. Lieutenant Macleod, of the Royal Navy, proposes to ascend the Niger in a steam-launch, and when up the country, to cross over to, and descend the Gambia, with a view to discover new sources of trade; and Mr Macgregor Laird is still ready to carry a vessel up any river of the western coast to which government may please to send him. Besides the travellers mentioned, there are others pushing their way in different parts of the south; and the French are not idle in the north--they have added to our information concerning Abyssinia, and the countries bordering on the Great Desert. But in addition to African geography, all these explorations have added to our knowledge of African geology. A vast portion of the interior is supposed to have been an inland sea, of which Ngami and other lakes are the remains; fossil bones of most peculiar character have been found, but only of terrestrial and fresh-water animals. A name is already given to a creature of a remote secondary period; Professor Owen, from the examination of a few relics, pronounces it to be a _Dicynodon_. According to Sir B. Murchison, such have been the main features of Africa during countless ages; 'for the old rocks which form her outer fringe, unquestionably