This invention was entered at the Patent Office on the 15th instant, by James K. Hobbs. The improvement consists in the placing of grate-bars at the bottom of the fire chamber, below which is an open air chamber into which the cinders and ashes fall through the grate, instead of accumulating and clogging the fire chamber. The cinders may be drawn out of the air chamber by an opening at the side of the forge. The blast is admitted above the grate, and the mouth of the air chamber being ordinarily closed, the blast is not affected by the grate. We think it must prove a useful invention.