battery is a 21 per cent. solution of
potassium hydrate having, in addition, a small amount of lithium
hydrate. The active metals of the electrodes--which will oxidize and
reduce in this electrolyte without dissolution or chemical
deterioration--are nickel and iron. These active elements are not put in
the plates AS METALS; but one, nickel, in the form of a hydrate, and the
other, iron, as an oxide.

"The containing cases of both kinds of active material (Fig. 1), and
their supporting grids (Fig. 2), as well as the bolts, washers, and nuts
used in assembling (Fig. 3), and even the retaining can and its cover
(Fig. 4), are all made of nickel-plated steel--a material in which
lightness, durability and mechanical strength are most happily
combined, and a material beyond suspicion as to corrosion in an alkaline
electrolyte....

"An essential part of Edison's discovery of active masetials for
an alkaline storage battery was the PREPARATION of these materials.
Metallic powder of iron and nickel, or even oxides of these metals,
prepared in the ordinary way, are not chemically active in a sufficient
degree to work in a battery. It is only when specially prepared iron
oxide of exceeding fineness, and nickel hydrate conforming to certain
physical, as well as chemical, standards can be made that the alkaline
battery is practicable. Needless to say, the working out of the
conditions and processes of manufacture of the materials has involved
great ingenuity and endless experimentation."

The article then treats of Edison's investigations into means for
supporting and making electrical connection with the active materials,
showing some of the difficulties encountered and the various discoveries
made in developing the perfected cell, after which the writer continues
his description of the "A" type cell, as follows:

"It will be seen at once that the construction of the two kinds of plate
is radically different. The negative or iron plate (Fig. 5) has the
familiar flat-pocket construction. Each negative contains twenty-four
pockets--a pocket being 1/2 inch wide by 3 inches long, and having a
maximum thickness of a little more than 1/8 inch. The positive or nickel
plate (Fig. 6) is seen to consist of two rows of round rods or pencils,
thirty in number, held in a vertical position by a steel support-frame.
The pencils have flat flanges at the ends (formed by closing in the
metal case), by which they are supported and electrical c