and crystals will then form on the
zinc. These will be very thin, and will adhere together, firmly, forming
a porous mass. This, when saturated and kept under water for a short
time, may be put into the openings of the negative plate.

[Illustration: _Fig. 63._ ASSEMBLAGE OF ACCUMULATOR PLATES]

CONNECTING UP THE PLATES.--The next step is to put these plates in
position to form a battery. In Fig. 63 is shown a collection of plates
connected together.

For simplicity in illustrating, the cell is made up of glass, porcelain,
or hard rubber, with five plates (A), A, A representing the negative and
B, B the positive plates. A base of grooved strips (C, C) is placed in
the batteries of the cell to receive the lower ends of the plates. The
positive plates are held apart by means of a short section of tubing
(D), which is clamped and held within the plates by a bolt (E), this
bolt also being designed to hold the terminal strip (F).

In like manner, the negative plates are held apart by the two tubular
sections (G), each of which is of the same length as the section D of
the positives. The bolt (H) holds the negatives together as well as the
terminal (I). The terminals should be lead strips, and it would be well,
owing to the acid fumes which are formed, to coat all brass work,
screws, etc., with paraffine wax.

The electrolyte or acid used in the cell, for working purposes, is a
pure sulphuric acid, which should be diluted with about four times its
weight in water. Remember, you should always add the strong acid to the
water, and never pour the water into the acid, as the latter method
causes a dangerous ebullition, and does not produce a good mixture.

Put enough of this solution into the cell to cover the tops of the
plates, and the cell is ready.

[Illustration: _Fig. 64._ CONNECTING UP STORAGE BATTERY IN SERIES]

CHARGING THE CELLS.--The charge of the current must never be less than
2.5 volts. Each cell has an output, in voltage, of about 2 volts, hence
if we have, say, 10 cells, we must have at least 25 volts charging
capacity. We may arrange these in one line, or in series, as it is
called, so far as the connections are concerned, and charge them with a
dynamo, or other electrical source, which shows a pressure of 25 volts,
as illustrated in Fig. 64, or, instead of this, we may put them into two
parallel sets of 5 cells each, as shown in Fig. 65, and use 12.5 volts
to charge with. In this case it will take doubl