ooking down through this opening we can see the things needed to form
a storage battery: the electrolyte, and the electrodes or "plates" as
they are called. If we should remove the lead bars connecting one cell
to another, and take off the black cover, we should find that the
posts which project out of the cells are attached to the plates which
are broad and flat, and separated by thin pieces of wood or rubber.,
If we lift out the plates we find that they are connected alternately
to the two lead posts, and that the two outside ones have a gray
color. If we pull the plates out from each Other, we find that the
plates next to the two outside ones, and all other plates connected to
the same lead post as these have a chocolate-brown color. If we remove
the jar of the cell, we find that it is made of hard rubber. Pouring
out the electrolyte we find several ridges which hold the plates off
the bottom of the jar. The pockets formed by these ridges may contain
some soft, muddy substance. Thus we have exposed all the elements of a
cell, posts, plates, "separators," and electrolyte. The gray colored
plates are attached to the "negative" battery post, while the
chocolate-brown colored ones are connected to the "positive" battery
post. Examination will show that each of the plates consists of a
skeleton metallic framework which is filled with the brown or gray
substances. This construction is used to decrease the weight of the
battery. The gray filler material is pure lead in a condition called
"spongy lead." The chocolate-brown filler substance is peroxide of
lead.

We have found nothing but two sets of plates--one of pure lead, the
other of peroxide of lead, and the electrolyte of sulphuric acid and
water. These produce the heavy current necessary to crank the engine.
How this is done, and what the chemical actions within the cell are,
are described in Chapter 4.

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CHAPTER 3.
MANUFACTURE OF STORAGE BATTERIES.
---------------------------------

To supply the great number of batteries needed for gasoline
automobiles, large companies have been formed. Each company has its
special and secret processes which it will not reveal to the public.
Only a few companies, however, supply batteries in any considerable
quantities, the great majority of cars being supplied with batteries
made by not more than five or six manufacturers. This greatly reduces
the number