controlled by dampers or stop-cocks, and this has given place to the
gas apparatus. Another simple form of oven, though not one which I
shall recommend, is a species of sheet-iron box, which is encased by
another and larger box of the same shape, so placed that from 2 to 3
inches of interspace exists between the two boxes. To this interspace
heat is applied, and a flue will have to be affixed to this apparatus
to carry off the vapours which arise from the enamel or japan. For
amateur or intermittent jobbing work the oven illustrated in Figs. 2
and 3 is about as good as any, though to guard against fire it would
be as well to have a course of brickwork beneath the oven, while if
this is not possible on account of want of height, a sheet or so of
zinc or iron will help to mitigate the danger. It is also advisable,
if the apartment is a low-pitched one, to have a sheet of iron or zinc
suspended by four corner chains from the ceiling in order to protect
this from firing through the heat from the enamelling oven. Of course,
it will be understood that every portion of the stove must be put
together with rivets, no soldered work being permissible.

[Illustration: FIG. 2.--Door of Oven when Shut.]

To those who wish to construct their own stove, it will be found that
the framework can be shaped out of 1-inch angle iron, the panels or
walls being constructed of sheet-iron of about 18 gauge, the whole
being riveted together. The front will be occupied in its entire space
by a door, which will require to be hung on strong iron hinges, and
the framework of this door should be constructed of 1 inch by 1/4 inch
iron--a rather stouter material will really be no disadvantage--to
which the sheet-iron plates must be riveted. In the centre of the door
must be cut a slit, say 1-1/2 inches by 9 inches, which will require
to be covered with mica or talc behind which must be placed the