gns of the rubber case was the bulging of the end, due to
the pull of the battery hold down rod on a small handle attached to
the center of the end. In the Philadelphia battery this has been
overcome by the use of a wide handle which snaps into openings in the
end of the case in such a way that the pull on the handle is
transferred to the sides. Another feature of this type handle is that
it is a separate piece snapped into the case without the use of any
metal insert in the rubber case, and if the handle should break, it
can be replaced at small expense without the use of any tools.

[Fig. 260 Philadelphia Diamond Grid Battery with rubber case]

The Philadelphia vent plug is of the bayonet type, and is tightened by
a quarter turn. The plug simply has a small vent hole in the top, and
may either be taken out or left on while battery is charging.

The Philadelphia Separator

The Philadelphia separator is made of quarter sawed hardwood. It has a
hard resinous wood in which the hard and soft portions occur in
regular alternating vertical layers. The soft layers are porous, and
permit the diffusion of the acid from plate to plate. The hard layers
give the separator stiffness and long life. The alternating hard and
soft layers are at right angles to the surface of the separator, so
that the electrolyte has a direct path between plates.

The methods of repairing Philadelphia Diamond Grid batteries are no
different from those already given, on pages 328 to 374.

When the elements of the old type batteries have been assembled and
returned to the jars, put the covers in place, and pour the compound
around the edges of the cover, and in the post wells. The old compound
must be removed from the petticoats on the posts before new compound
is poured in. The compound must be warm and thin enough to flow around
and fill up the petticoat spaces on the posts in order to get a good
seal. When the post wells are full of compound, and while compound is
still warm, put on the square sealing washers and press them down so
that the holes in the washers fit closely around the octagonal part of
the posts.

THE EVEREADY STORAGE BATTERY

It is claimed by the manufacturers that the sulphate which forms in
the Eveready battery during discharge always remains in the porous,
convertible form, and never crystallizes and becomes injurious, even
though the battery is allowed to stand idle on open circuit for a
considerable length of t