ve material of frozen
positives also fills up the pores of a separator.

6. Edges Chiseled Off. A buckling plate will cut through the lower
edge of a separator and short circuit the cell. Holes will be cut
through any part of a separator by a buckling plate, or a negative
with bulged active material.

JAR TROUBLES

Battery jars are made of hard rubber, and are easily broken. They are
not acted upon by the electrolyte, or any of the impurities which may
be found in the jar. Their troubles are all mechanical, and consist of
being cracked, or having small holes through the walls. Jars are
softened by high temperatures, but this does no particular harm unless
they are actually burned by an open flame or red hot metal. The causes
of jar troubles are as follows:

1. Rough Handling. By far the most common cause of jar breakage is
rough handling by careless or inexperienced persons. If one end of a
battery rests on the floor, and the other is allowed to drop several
inches, broken jars will probably result from the severe impact of the
heavy lead plates. Storage batteries should be handled as if made of
glass. When installed on a car, the springs protect the battery from
shock to a considerable extent, but rough roads or exceptionally
severe jolts may break jars.

2. Battery Not Properly Fastened. In this case a battery is bumped
around inside the battery compartment, and damage is very likely to
result.

3. Any Weight Placed on Top of the Battery is transmitted from the
links to the plates, and by them to the bottom of the jars. Batteries
should always be stored in racks, and not one on top of another. The
practice of putting any weight whatever on top of a battery should be
promptly discouraged.

4. Freezing. This condition has already been explained. It causes a
great many broken jars every winter.

5. Groups Not Properly Trimmed. The outside negative plates in a cell
come just inside the jar, and the strap ends must be carefully trimmed
off flush with the plates, to prevent them from breaking the top of
the jars. Jars have slightly rounded corners, and are somewhat
narrower at the extreme ends than nearer the center. A group may
therefore go into a jar quite readily when moved toward the other end
of the jar to that into which the post strap must go when in proper
position for the cover. When the group is forced back into its proper
position the strap may break the jar. It is a good plan not only to
trim the