At San Francisco they purchased a large house as a trading establishment and depot for merchandise; and they intend this year to have a place of the same kind at each of the principal ports in Upper California. Two vessels are building in London, intended for the same trade—that is, for the coasting trade; and after completing their cargoes, to carry them to England. These things, with others, give every indication that it is the purpose of the Hudson’s Bay Company to monopolize the whole hide and tallow trade of California, a trade which now employs more than half a million of American capital. At the Sandwich Islands the company have a large trading establishment, and have commenced engaging the commerce of the country, with evident designs to monopolize it, if possible, and to drive off the Americans, who have heretofore been its chief creators and conductors. I have been informed, by one of the agents of the Hudson’s Bay Company, that the agricultural and commercial operations of the English at Puget Sound, Columbia River, California, and Sandwich Islands, are carried on, not actually by the Hudson’s Bay Company, but by what may be termed a branch of it—by gentlemen who are the chief members and stockholders of said company, and who have associated themselves under the firm Pelly, Simpson & Co., in London, and with a capital of more than $15,000,000! Seeing these companies, then, marching with iron footsteps to the possession of the most valuable portion of country in the Northern Pacific, and considering, too, the immense amount of their capital, the number, enterprise, and energy of their agents, and the policy pursued by them, great reason is there to fear that American commerce in that part of the world must soon lower its flag. But, sir, it is to be hoped that our government will soon do something to break up the British settlements in the Oregon Territory, and thereby destroy the source from which now emanates the dire evils to American interests in the western world. In the endeavor to bring about that desirable object, you have done much; and every friend to his country, every person interested in the commerce of the Pacific, must feel grateful for the valuable services rendered them by you. With great respect, your obedient servant, HENRY A. PRICE. HON. LEWIS F. LINN, Senator of the United States, Washington. [From the _Tribune_ (New York), July 4, 1842.] SCIENTIFIC EXPEDITION.