and circulates it along the pipes to the bearings. The course of the oil
is as follows: The oil is forced by the propeller, I, and oils the
bearing, A. The greater part passes along the pipe, E, to the end
bearing, C; some after oiling the bearing, C, drains back by the pipe,
F, to the reservoir, D; the remaining oil passes along through the
armature spindle, oils the bearings, B, and drains into the reservoir,
D, from which the oil is again drawn along the pipe, G, into the stand
pipe, H, by the suction of the fan, K. The suction of the fan is also
connected to the diaphragm, L, and forms, with it and the spring, M, the
principal part of the governor which actuates the throttle valve, V.
Fig. 4 is the electrical control governor, which will be further
described in connection with the dynamo. It acts directly upon the
controlling diaphragm, L, by admitting or closing a large access of air
to it, and thus exercises a controlling influence upon it.

The dynamo which forms the other portion of the electric generator, Fig.
1, is coupled to the motor spindle by a square tube coupling fitted on
to the square spindle ends. The armature is of the drum type. The body
is built up of thin iron disks threaded on to the spindle and insulated
from each other by tracing paper. This iron body is turned up and
grooves milled out to receive the conducting wires. For pressures of 60
to 80 volts there are fifteen convolutions of wire, or 30 grooves. The
wire starting at b, Fig. 6, is led a quarter of a turn spirally, c,
round the cylindrical portion, a, then passing along a groove
longitudinally is again led a quarter turn spirally, d, round the
cylindrical portion, a, then through the end washer, and back
similarly a quarter turn, e, then led along the diametrically opposite
groove, and lastly a little over a quarter turn, f, back to g, where
it is coupled to the next convolution. The commutator is formed of rings
of sections. Each section is formed of short lengths. Each length is