Count Rumford understood that fireplaces produce radiant heat, and at about 1795 he came up with a design to take advantage of that effect. Although he was an American, Rumford developed his fireplace in England. His fireplaces were shallow, with widely angled covings and light-colored masonry materials. He experimented with the shape of the throat "to find out and remove those local hindrances which prevent the smoke from following its natural tendency to go up the chimney." Rumford rounded the breast and reduced the size of the throat to a narrow, streamlined slit measuring only about 1/20 the size of the standard fireplace opening. It forms a nozzle through which the smoke and air flow at an increased speed, and
