Recent occurrences in China have been unfavorable to a revision of the treaty with that Empire of the 3d July, 1844, with a view to the security and extension of our commerce. The twenty-fourth article of this treaty stipulated for a revision of it in case experience should prove this to be requisite, "in which case the two Governments will, at the expiration of twelve years from the date of said convention, treat, amicably concerning the same by means of suitable persons appointed to conduct such negotiations." These twelve years expired on the 3d July, 1856, but long before that period it was ascertained that important changes in the treaty were necessary, and several fruitless attempts were made by the commissioner of the United States to effect these changes. Another effort was about to be made for the same purpose by our commissioner in conjunction with the ministers of England and France, but this was suspended by the occurrence of hostilities in the Canton River between Great Britain and the Chinese Empire. These hostilities have necessarily interrupted the trade of all nations with Canton, which is now in a state of blockade, and have occasioned a serious loss of life and property. Meanwhile the insurrection within the Empire against the existing imperial dynasty still continues, and it is difficult to anticipate what will be the result. Under these circumstances I have deemed it advisable to appoint a distinguished citizen of Pennsylvania envoy extraordinary and minister plenipotentiary to proceed to China and to avail himself of any opportunities which may offer to effect changes in the existing treaty favorable to American commerce. He left the United States for the place of his destination in July last in the war steamer _Minnesota_. Special ministers to China have also been appointed by the Governments of Great Britain and France. Whilst our minister has been instructed to occupy a neutral position in reference to the existing hostilities at Canton, he will cordially cooperate with the British and French ministers in all peaceful measures to secure by treaty stipulations those just concessions to commerce which the nations of the world have a right to expect and which China can not long be permitted to withhold. From assurances received I entertain no doubt that the three ministers will act in harmonious concert to obtain similar commercial treaties for each of the powers they represent. We can not fail to feel a deep interest in all that concerns the welfare of the independent Republics on our own continent, as well as of the Empire of Brazil. Our difficulties with New Granada, which a short time since bore so threatening an aspect, are, it is to be hoped, in a fair train of settlement in a manner just and honorable to both parties.