en driven to keep
them in place until all were in position and the whole could be
clamped down. In the middle of the pieces 1/4-in. holes, B, were
then drilled and 1/4-in. bolts put in and tightened up, large
holes being cut through the wood to enable this to be done. The
armature tunnel was then carefully filed out and all taken apart
again so that the rough edges could be scraped off and the
laminations given a thin coat of shellac varnish on one side.
After assembling a second time, the bolts were coated with shellac
and put into place for good. Holes 5-32 in. in diameter were
drilled in the corners, A, and filled with rivets, also varnished
before they were put in. When put together they should make a
piece 2 in. thick.

This peculiar construction was adopted because proper stampings
were not available, and as every bit of sheet iron had to be cut
with a small pair of tinners' snips, it was important to have a
very simple outline for the pieces. They are not particularly
accurate as it is, and when some of them got out of their proper
order while being varnished, an awkward job occurred in the magnet
which was never entirely corrected. No doubt some energy is lost
through the large number of joints, all representing breaks in the
magnetic circuit, but as the laminations are tightly held together
and the circuit is about as compact as it could possibly be,
probably the loss is not as great as it would appear at first
sight.

The rotor is made of laminations cut from sheet iron, as shown in
Fig. 3, which were varnished lightly on one side and clamped on
the shaft between two nuts in the usual way. A very slight cut was
taken in the lathe afterwards to true the circumference. The shaft
was turned from 1/2-in. wrought iron, no steel being obtainable,
and is shown with dimensions in Fig. 4. The bearings were cast of
babbitt metal, as shown in Fig. 5, in a wooden mold and bored to
size with a twist drill in the lathe. They are fitted with
ordinary wick lubricators. Figures 6 and 7 are sections showing
the general arrangement of the machine.

The stator is wound full with No. 22 double cotton-covered copper
wire,

[Illustration: Motor]

about 2-1/2 lb. being used, and the connections are such as to
produce alternate poles--that is, the end of the first coil is
joined to the end of the second the beginning of the second to the
beginning of the third, and the end of the third to the end of the
fourth, while the beg