SCIENTIFIC EXPEDITIONS.—In the Supplement of our December number we gave the outline of an expedition to be sent by the United States, into the Pacific, on scientific purposes; and for some time past we have heard rumours of another voyage round the world by the French. The fiat has at length passed, as our readers will see by the following sketch of its projected route.

The king of the French has, by a decision of the 26th of March, approved of a proposal for a new voyage round the world, the conducting of which is to be confided to M. Dumont D’Urville. Two vessels will be employed in this expedition; the Astrolabe, commanded by Captain D’Urville, and the Zelee, by Captain Jacquinot. These vessels will sail from Toulon about the beginning of September, and touching at Cape Verds will proceed due south into the polar sea between the meridians of Sandwich land and South Shetland, to pursue Weddel’s track, who it will be remembered reached the lat. of 74° 15’. The vessels will penetrate as far south as possible, and return to Magellan Strait, where ample work is yet left in the examination of the numerous sounds and inlets in the adjacent archipelago of islands. From hence the vessels will proceed to Chiloe, and thence to Valparaiso, to refit, &c. In the spring of 1838 they will depart from Valparaiso for the Polynesian Archipelago, and in June will be at Vavoo, where M. D’Urville will finish the work left undone by Astrolabe in 1827. Banks Islands, to the north of the New Hebrides, and Van Icoro will next be visited, and afterwards the Solomon islands, from whence, if the state of the vessels and crews permit, M. D’Urville will pass through Torres Straits and visit the new Dutch colony on the river D’Ourga, Aroo and Key Islands, and thence proceed to Amboina. It is intended the Zelee shall then return to France, bringing with her the collections made. The Astrolabe will pursue her voyage towards New Holland, and in the latter part of 1838 will be at Swan River. She will go thence to Hobart Town and New Zealand, and make a careful survey of Cooks strait. She then proceeds to Chatham island and continues northward to the Caroline islands, afterwards to Mindanao, Borneo and Sumatra, and will then return to France by Cape of Good Hope. We look on this as a most interesting expedition, and one that will yield important results. We cannot, however, but regret to see so extensive and important an island as New Guinea, left year after year in its original neglected condition, with but little addition to its coasts since the time of Dampier.