"[T]he form of the breast of the Chimney is... of... great importance... The worst form it can have is that of a vertical plane, or upright flat;—and next... worst... is an inclined plane.—Both... cause the current of warm air from the room, which will... sometimes find its way into the Chimney, to cross upon the current of smoke, which rises from the fire, in a manner, most likely to embarrass it in its ascent, and drive it back.— The inclined plane which is formed by a flat register placed in the throat of a Chimney produces the same effects; and this is one reason, among many... which have induced me to disapprove of register stoves."