The fitness of cast iron for reproducing works of art has lately been beautifully illustrated by a medallion head of Washington, enclosed in an oval frame, and embellished with branches of oak and palm, secured by a ribbon, forming an allegorical design, the whole being in iron. The mold was made by A. W. Jones, of this city, and the likeness is the result of much research, being a compromise between the portraits taken by Stuart and Trumbull, and representing him as, at once, the hero and the sage. These heads have been remarkably well cast under the superintendence of the artist, by Messrs. Russel & Beach ; and as castings, they will favorably compare with any of those works of art in cast iron, of an equal size, that are sent from the foundries of Berlin. Mr. W. Hallison gave his assistance in their production, and they are now for sale by Mr. Hart, at the warerooms of Boardman, Gray & Co., No. 487 Broadway, this city. We understand that Mr. Hart intends visiting our principal cities* and that the head of Henry Clay is shortly to be produced. The size is 42 X 30 inches. We hope that this form of honoring our great men will be liberally patronized by the people, for it opens a new era in the history of American practical art.