Still, however, we possess some general notice, and some vague reports of all these countries; but it is otherwise with respect to the unknown portions of Africa.  The whole of this quarter of the world, from the Niger to the confines of the British settlement at the Cape of Good Hope, may, with little limitation, be considered as unknown.  Travellers have indeed penetrated a short distance from the western coast into the interior, in some parts between the latitude of the Niger and the latitude of the extreme northern boundary of the Cape settlement:  and a very little is known respecting some small portions of the districts closely adjoining to the eastern coast; but the whole of central Africa is still unexplored, and presents difficulties and dangers which it is apprehended will not be speedily or easily overcome.  To the north of the Niger lies the Sahara, or Great Desert; of this, probably, sufficient is known to convince us that its extent is such, that no country that would repay a traveller for his fatigue and risk, is situated to the north of it.  To the east of the Niger, however, or rather along its course, and to the north of its course, as it flows to the east, much remains to be explored; many geographical details have been indeed gathered from the Mahomedan merchants of this part of Africa, but these cannot entirely be trusted.  The course and termination of the Niger itself is still an unsolved problem.

Captain Scoresby, a most intelligent and active captain in the whale fishery trade, has very lately succeeded in reaching the eastern coasts of Greenland, and is disposed to think that the descendants of the Danish colonists, of whose existence nothing is known since this coast was blocked, up by ice at the beginning of the fifteenth century, still inhabit it.  The northern shores of Greenland, and its extent in this direction are still unknown.

Notwithstanding the zeal and success with which the government of the United States prosecute their discoveries to the west of the Mississippi, there is still much unexplored country between that river and the Pacific Ocean.  It is possible that lands may lie within the antartic circle, of which we have hitherto as little notion as we had of South Shetland ten years ago; but if there are such, they must be most barren and inhospitable.  It is possible also, that, notwithstanding the care and attention with which the great Pacific has been so repeatedly swept, there may yet be islands in it undiscovered; but these, however fertile from soil and climate, must be mere specks in the ocean.