The President has appointed Rufus L. B. Clarke, Esq., of Mt. Pleasant, Iowa, to the position of Examiner-in-Chief of the Patent Office, to fill the vacancy existing in that Board. Mr. Clarke is a brother of " Grace Greenwood," and is a lawyer by profession, having been admitted to the bar by the Supreme Court of this State in 1845, and practiced his profession at Rochester, N. Y., until the fall of 1845 when he emigrated to Iowa. During his residence in Rochester he was one of the editors and proprietors of the Evening Gazette. At Mt. Pleasant, Iowa, Mr. Clarke, in company with George Doolittle, opened a law office and soon acquired a large practice; being offered the honorable position of law clerk in the Comptroller's office, at Washington, he removed to that city, where he has since remained in charge of special cases and questions arising in the settlement of war claims. He is said to be a gentleman of ability.