In storage battery cells, the formation of a hard white basic lead
sulphate, Pb2 S05. Its formation is due to over-exhaustion of the cells.
As long as the voltage is not allowed to fall below 1.90 volts per cell
little of it forms. As it accumulates it is apt to drop off the plate
and fall to the bottom, thus weakening the plate possibly, and depriving
it of active material, and clogging up the cell. If it carries a film of
metallic lead with it, there is danger of short circuiting the cell.

The presence of some sodium sulphate in the solution is said to tend to
prevent sulphating, or to diminish it.

Sulphur Dioxide.
A compound gas, S O2; composed of
Sulphur,            32
Oxygen,             32
Molecular weight,   64
Specific gravity,    2.21.

It is a dielectric of about the same resistance as air. Its specific
inductive capacity at atmospheric pressure is: 1.0037 (Ayrton).

Synonyms–Sulphurous Acid–Sulphurous Acid Gas.