Any angle can be given glass tubing in this way. Connect
the glass tube to B with a short piece of rubber hose, E. If the
hose is not a tight fit, bind with a short piece of fine copper
wire. The standard, F, is made from a piece of No. 10 wire about
10 in. long. To this standard solder the supporting wire, G--No.
14 wire will do. On one side bend the wire around the tube B, and
on the other around the glass tube, D.
The base, H, can be made of oak, stained and varnished. The bottom
of the box, A, is covered with lampblack so as to readily absorb
all heat that strikes the surface. The black should not be put on
until just before you paint the supports, cover and rim of the box
with gold or silver paint. Hold the bottom of the box to be
blackened over a little burning cotton saturated with turpentine.
The scale on the glass can be etched with hydrofluoric acid, or
made with a little black paint. The water can be put in with a
medicine dropper. This instrument will measure the amount of heat
given by a candle some 20 or 30 ft. away.
--Contributed by J. Thos. Rhamstine.
** Home-Made Battery Voltmeter [153]
Secure a piece of brass tube 3 in.
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