Abstract: In a combination of a furnace which is provided with an upwardly opening mouth, a lid for the mouth, a hood associated with the furnace and enclosing the mouth, the hood having a ceiling disposed above the uppermost position of the lid and the ceiling being formed with a port registering with the furnace mouth, and a cover for the port, the improvement in which the lid is supported upon a generally vertically upwardly extending post for swinging movement with the post about a substantially vertical axis outside the boundary of the mouth between a position in registry with the mouth and a position laterally removed from such registry, and the cover being mounted upon the post for swinging movement about the axis with the post and the lid.