onnection is
made. The frame is slit at the inner horizontal edges, and then folded
in such a way as to make individual clamping-jaws for each end-flange.
The clamping-in is done at great pressure, and the resultant plate has
great rigidity and strength.

"The perforated tubes into which the nickel active material is loaded
are made of nickel-plated steel of high quality. They are put together
with a double-lapped spiral seam to give expansion-resisting qualities,
and as an additional precaution small metal rings are slipped on the
outside. Each tube is 1/4 inch in diameter by 4 1/8 inches long, add has
eight of the reinforcing rings.

"It will be seen that the 'A' positive plate has been given the
theoretically best design to prevent expansion and overcome trouble from
that cause. Actual tests, long continued under very severe conditions,
have shown that the construction is right, and fulfils the most sanguine
expectations."

Mr. Holland in his article then goes on to explain the development of
the nickel flakes as the conducting factor in the positive element, but
as this has already been described in Chapter XXII, we shall pass on to
a later point, where he says:

"An idea of the conditions inside a loaded tube can best be had by
microscopic examination. Fig. 7 shows a magnified section of a regularly
loaded tube which has been sawed lengthwise. The vertical bounding walls
are edges of the perforated metal containing tube; the dark horizontal
lines are layers of nickel flake, while the light-colored thicker layers
represent the nickel hydrate. It should be noted that the layers of
flake nickel extend practically unbroken across the tube and make
contact with the metal wall at both sides. These metal layers conduct
current to or from the active nickel hydrate in all parts of the tube
very efficiently. There are about three hundred and fifty layers of
each kind of material in a 4 1/8-inch tube, each layer of nickel hydrate
being about 0.01 inch thick; so it will be seen that the current does
not have to penetrate very far into the nickel hydrate--one-half a
layer's thickness being the maximum distance. The perforations of
the containing tube, through which the electrolyte reaches the active
material, are also shown in Fig. 7."

In conclusion, the article enumerates the chief characteristics of the
Edison storage battery which fit it preeminently for transportation
service, as follows: 1. No loss of active m