quickly formed.


THE HEATING EFFECT OF THE CURRENT.

With a piece of very fine platinum wire (No. 36 or 40), placed in the
circuit of the battery, the heating effect of the current may be
shown. A half inch of No. 36 platinum wire will serve for the
experiment. If the battery is in good condition it will heat from 1/8
to 1/4 inch of the wire red hot. This is sufficient to light gas or an
alcohol lamp, also to ignite powder or gun cotton.

A short piece of a watch hair spring, or a piece of very fine iron
wire, if placed in the circuit will be made very hot.


DUPLICATION OF BATTERIES.

Should the experimenter desire to go more deeply into the effects of
the current, he will need a more powerful battery. The battery
described has been made on a very simple plan, to enable the amateur
to copy it without difficulty or great expense. There is no mystery
about the battery. Any one can make it. All that is required is a
plate of zinc, two plates of carbon, some strips of wood and copper,
and two common wood screws for each cell. The tumblers may be had
anywhere.

Although it is advisable to use insulated wire for making the
electrical connections, bare wires may be used if care is taken in
arranging them, so that they will not touch each other or other