Mr. Clay’s official letter to Mr. Middleton, our minister at Russia, dated May tenth, 1825, is a paper of great polish and skill. Mr. Clay had witnessed, for seventeen years, the devastating wars which had raged between Spain and her South American colonies, and fervently desired to see them terminated. For this purpose, he projected and prepared the document aforesaid, independent of all suggestion or aid, from any public functionary. He had familiarized himself with the facts connected with these wars, which, in the most striking and beautiful manner, he spread out before the emperor, and urged him to use his influence in bringing about an event which he so ardently desired. This communication was so skilfully and ingeniously framed, as to direct the attention of Alexander to the struggling Greeks, and enlist his influence in their behalf, which was precisely what the writer wished, though he did not say so in so many words. Mr. Clay’s efforts were triumphantly successful. The emperor instructed his minister at the Spanish court, to use every proper exertion to terminate these sanguinary conflicts, which eventuated in the acknowledgement of South American independence, by the parent country. The emperor also took sides with the Greeks, made certain proposals, relative to them, to the grand sultan, and, on their being rejected, instantly set about making preparations to march against him. Before their completion he deceased, but his successor took them up, and struck a blow so decisive as to put an instant period to his barbarities. Thus Mr. Clay’s influence, through this instrument, set in motion means that moved both hemispheres, and accomplished results, the sum of whose benefits and blessings, never has been, and never can be, ascertained.