arge. At this time all the cells should be gasing, but not as
freely as on an overcharge.

_Low Cells._ An unhealthy condition in a cell usually manifests itself
in one of the following ways: Falling off in specific gravity or voltage
relative to the rest of the cells, lack of gasing when charged, and
color of the plates, either noticeably lighter or darker than those of
other cells of the battery. When any of the above conditions are found
in a cell, the cell should receive immediate attention, as a delay may
mean serious trouble. The cell should be thoroughly inspected to
determine if a short-circuit exists, either caused by some foreign
substance, by an excess of sediment in the bottom of the tank, or by
portions of the plates themselves. If such a condition is found, the
cause should be immediately removed and, if the defect has been of short
duration, the next overcharge will probably restore it to normal
condition. If the defect has existed for some time, it is often
necessary to give the cell a separate charge. This may be done by
connecting it directly to the charging generator with temporary leads
and thus bring it back to its normal condition. It is sometimes found
necessary to replace the cell in order to restore the battery to its
normal condition.

_Sediment._ The cells of the battery should be carefully watched to
prevent the sediment which collects in the bottom of the jar or tank
during use from reaching the bottom of the plates, thereby causing short
circuits between them. When the sediment in the cell has reached within
one-half inch of the bottom of the plates, it should be removed at once.
With small cells using glass jars this can most easily be done directly
after an overcharge by carefully drawing off the electrolyte without
disturbing the sediment and then removing it from the jar. The plates
and electrolyte should be replaced in the jar as soon as convenient to
prevent the plates from becoming dry. If the plates are large and in
wooden tanks, the sediment can most easily be removed by means of a
scoop made especially for the purpose. The preferable time to clean the
tanks is just before an overcharge.

_Replacing Batteries._ There comes a time in the life of nearly every
central-office equipment when the storage battery must be completely
renewed. This is due to the fact that the life of even the best of
storage batteries is not as great as the life of the average switchboard
equipment. It ma