p and bottom, and your kiln is
ready for business. The handle of the pail will be convenient for
moving it about, and it can be set on three bricks or some more
elaborate support, as dictated by fancy and expense.

The temperature required for baking earthenware is 1250
degrees--1310 degrees, C.,; hotel china, 1330 degrees; hard
porcelain, 1390 degrees-1410 degrees. These temperatures can not
be obtained in the above kiln by means of the ordinary Bunsen
burner. If will be necessary either to buy the largest size
Bunsen, or make one yourself, if you have the materials. If you
can get a cone which can be screwed into an inch pipe, file the
opening of the cone to 1/16 in. diameter, and jacket the whole
with a 2-1/2-in. pipe. The flame end of this burner tube should be
about 4-1/2 in. above the cone opening and should be covered with
gauze to prevent flame from snapping back. When lighted, the point
of the blue flame, which is the hottest part, should be just in
the hole in the bottom of the kiln. Such a burner will be cheaply
made and will furnish a kiln temperature of 1400 degrees, but it
will burn a great deal of gas.

A plumber's torch of medium size will cost more in the beginning,
but will be cheaper in operation. Whatever burner is used, the
firing should be gradual, and with especial caution the first
time. By experiment you will find that a higher temperature is
obtained by placing a 1-in. pipe 2-ft. long over the lid hole as a
chimney. It would be still more effective to get another iron
pail, 2 in. wider than the kiln, and get a down draft by inverting
it over the kiln at whatever height proves most suitable. --G. L.
W.

** How to Make a Small Medical Induction Coil [63]

The coil to be described is 3-1/2 in., full length of iron core,
and 3/4 in. in diameter.

Procure a bundle of small iron wire, say 1/4 in. in diameter, and
cut it 3-1/2 in. long; bind neatly with coarse thread and file the
ends smooth (Fig. 1). This done, make two wood ends, 1-1/4 by
1-1/4 in. and 3/8 in. thick, and varnish. Bore holes in the center
of each so the core will fit in snugly and leave about 1/4 in.
projecting from each end (Fig. 1).

After finishing the core, shellac two layers of thick paper over
it between the ends; let this dry thoroughly. Wind two layers of
bell magnet wire over this, allowing several inches of free wire
to come through a hole in the end. Cover with paper and shellac as
before. Wind about 1/8 in.