We publish the subjoined letter, received by one of our citizens a few days since, from a gentleman who accompanied the Oregon emigration last year [1843]. We give it entire, that our readers may have all the information that can be gathered from this section of the country. It is not so favorable, in some respects, of the Oregon Territory, as the accounts of others, but it is by no means disparaging. Mr. Gilpin thinks that corn can be raised to advantage, and says that the reason why they have none, is--because they plant none. It is undoubtedly a fine country for all the small grains and is unsurpassed as a grazing country. The emigrants who went out the past season have made a great change in business, and money now circulates on the Columbia as well on this side of the mountains, and everything begins to assume the appearance of civilization, business, trade, and the refinements this side the mountains. We see that Mr. Cushing, our minister to China, has returned by way of the city of Mexico; and here we have a letter from one of our enterprising citizens from the _halfway house_--the Sandwich Islands. We have been in the habit of looking to Europe for Asiatic news; let our government establish a chain of posts from this to Oregon, an overland mail will speedily follow, and the China and East India trade will pour into our channels of commerce from the gorges of the Rocky Mountains: and a journey from New York to China, by way of Oregon, will be less thought of than it formerly was to Saint Louis. The Government should consider that a little enterprise will place the East India trade at our door; and the sooner the better. We hope Congress, this winter, will take active measures to bring about such a state of things. What is a few thousand dollars compared with the object to be acquired? LAHIANA, MAUI, Sandwich Islands, July 17, 1844. _J. Wells, Esq._--