In AFRICAN DISCOVERY greater advances have been made in the last two years than before since the journeys of the brothers Lander. We mentioned in the last _International_ that the American traveller, Dr. W. Mathews, had been heard of at Vienna, and we now learn that he has been very successful in the five years of his adventure in the northern and central parts of the continent. Letters received in Berlin from Drs. Barth and Overweg, contain information of their having accomplished the journey across the Great Desert, or Sahara, and of their arrival near the frontiers of the kingdom of Air or Asben, (Air is the modern Tuarick, and Asben the ancient Sudan name), the most powerful in that part of Africa after Bornou, and never explored by Europeans. On the 24th of August--the date of their last letter--they were at Taradshit, a small place in about 20 deg. 30' N. latitude, and 9 deg. 20' longitude E. of Greenwich. Among their discoveries are some of peculiar interest, one of which is of several curious and very ancient sculptures, apparently of Egyptian origin. The King of Prussia has, at the instance of the Chevalier Bunsen and Baron Alexander von Humboldt, augmented the funds of the two travellers by a grant of 1,000 thalers. While Richardson, Barth and Overweg have penetrated the _terra incognita_ of the north, Dr. Krapf and the Rev. Mr. Rebmann have explored the region described on the common maps as the "Great Southern Sahara," and found it to be fertile, healthy, abounding in mountains, valleys and rivers, and inhabited by a race altogether superior to that which occupies the Atlantic coast. Mr. Mansfield Parkyns is endeavoring to cross the country southward from the Nile to the river Gambia; Mr. Charles Johnson is travelling in Abysinnia; Baron von Mueller is conducting an expedition up the White Nile; and the American missionaries and colonists are gradually extending their knowledge over the various settlements on the eastern coast of the continent. * * * * * THE PRUSSIAN EXPEDITION TO EGYPT, _Denkmaeler aus AEgypten und AEthiopien nach den Zeichnungen der von Sr. Majestat dem Koenige von Preussen Friedrich Wilhelm IV. nach diesen Laendern gesendeten, und in den Jahren 1842-45, ausgefuhrten wissenschaftlichen Expedition: Herausgegeben von Dr. R. Lepsius_; published at the expense and under the guarantee of the Prussian Government, will be completed in eighty parts, or eight hundred plates. Most of the plates are printed with tints, and many in the colors of the originals. This work forms a necessary completion of the celebrated work of the French Expedition under Napoleon. Parts I. to X. are now advertised as ready for subscribers, in London, at three dollars and a half each. * * * * * A NEW WORK ON AFRICA, by H. C. Grund, is advertised at Berlin. * * * * *