to burn them). Now, with short, thin wedges of wood, (new dry
separators generally answer the purpose), crowd down on the outside
edges of the jar, until you have the upper edge of jars straight and
even all around. If the jars are set in compound, take a hot
screwdriver and remove the compound from between the jar and case
near the top. If the cracks between cover and jar still remain, calk
them with asbestos packing, tow, or ordinary wrapping string. Do not
use too much packing;--just enough to close the cracks is sufficient.
When this is done, see that the top of the case is perfectly level, so
that when the compound is poured in, it will settle level all around
the upper edge of the case.

Sealing Compounds

There are many grades of compounds (see page 149), and the kind to use
must be determined by the type of battery to be sealed. There is no
question but that a poor grade used as carefully as possible will soon
crack and produce a slopper. A battery carelessly sealed with the best
compound is no better.

The three imperative conditions for a permanent lasting job are:

1. Use the best quality of the proper kind of compound for sealing the
battery on hand.

2. All surfaces that the compound comes in contact with must be free
from acid and absolutely clean and dry.

3. The sealing must be done conscientiously and all details properly
attended to step by step, and all work done in a workmanlike manner.

With respect to sealing, batteries may be divided into two general
classes. First, the old type battery with a considerable amount of
sealing compound. This type of battery generally has a lower and an
upper cover, the vent tube being attached or removable, depending on
the design. The compound is poured on top of the lower cover and
around the vent tube, and the top covers are then put on. Most of the
batteries of this type have a thin hard rubber sleeve shrunk on the
post where the compound comes in contact with it; this hard rubber
sleeve usually has several shallow grooves around it which increase
its holding power. This is good construction, provided everything else
is normal and the work properly done with a good stick-, compound.
There are a few single cover batteries with connecting straps close to
top of covers, and the compound is poured over the top of the straps.
See Fig. 262.

The second general type consists of single one-piece cover batteries
that have small channels or spaces around the