ve or negative, joined to a
strap. Groups do not include separators.

Hold-Down. Device for keeping separators from floating or working up.

Hold-Down Clips. Brackets for the attachment of bolts for holding the
battery securely in position on the car.

Hydrogen Flame. A very hot and clean flame of hydrogen gas and oxygen,
acetylene, or compressed air used for making burned connections.

Hydrogen Generator. An apparatus for generating hydrogen gas for lead
burning.

Hydrometer. An instrument for measuring the specific gravity of the
electrolyte.

Hydrometer Syringe. A glass barrel enclosing a hydrometer and provided
with a rubber bulb for drawing up electrolyte.

Jar. The hard rubber container holding the element and electrolyte.

Lead Burning. Making a joint by melting together the metal of the
parts to be joined.

Lug. The extension from the top frame of each plate, connecting the
plate to the strap.

Maximum Gravity. The highest specific gravity which the electrolyte
will reach by continued charging, indicating that no acid remains in
the plates.

Mud. (See Sediment.)

Negative. The terminal of a source of electrical energy as a cell,
battery or generator through which current returns to complete
circuit. Generally marked "Neg." or "-".

Ohm. The unit of electrical resistance. The smaller the wire conductor
the greater is the resistance. Six hundred and sixty-five feet of No.
14 wire (size used in house lighting circuit) offers I ohm resistance
to current flow.

Oil of Vitriol. Commercial name for concentrated sulphuric acid (1.835
specific gravity). This is never used in a battery and would quickly
ruin it.

Over-Discharge. The carrying of discharge beyond proper cell voltage;
shortens life if carried far enough and done frequently.

Paste. The mixture of lead oxide or spongy lead and other substances
which is put into grids.

Plate. The combination of grid and paste properly "formed." Positive$
are reddish brown and negatives slate gray.

Polarity. An electrical condition. The positive terminal (or pole) of
a cell or battery or electrical circuit is said to have positive
polarity; the negative, negative polarity.

Positive. The terminal of a source of electrical energy as a cell,
battery or generator from which the current flows. Generally marked
"Pos." or "+".

Post. The portion of the strap extending through the cell cover, by
means of which connection is made to the adjoining cell or t