. Clarke, one of the earliest electrical engineers
employed by Mr. Edison, made a number of tests on this 1882 railroad. I
believe that the engine driving the four Z generators at the power-house
indicated as high as seventy horse-power at the time the locomotive was
actually in service."

The electrical features of the 1882 locomotive were very similar
to those of the earlier one, already described. Shunt and series
field-windings were added to the motor, and the series windings could
be plugged in and out of circuit as desired. The series winding was
supplemented by resistance-boxes, also capable of being plugged in or
out of circuit. These various electrical features are diagrammatically
shown in Fig. 2, which also illustrates the connection with the
generating plant.

We quote again from Mr. Hammer, who says: "The freight-locomotive had
single reduction gears, as is the modern practice, but the power was
applied through a friction-clutch The passenger-locomotive was very
speedy, and ninety passengers have been carried at a time by it; the
freight-locomotive was not so fast, but could pull heavy trains at a
good speed. Many thousand people were carried on this road during 1882."
The general appearance of Edison's electric locomotive of 1882 is shown
in the illustration opposite page 462 of the preceding narrative. In the
picture Mr. Edison may be seen in the cab, and Mr. Insull on the front
platform of the passenger-car.

XIV. TRAIN TELEGRAPHY

WHILE the one-time art of telegraphing to and from moving trains was
essentially a wireless system, and allied in some of its principles to
the art of modern wireless telegraphy through space, the two systems
cannot, strictly speaking be regarded as identical, as the practice of
the former was based entirely on the phenomenon of induction.

Briefly described in outline, the train telegraph system consisted of
an induction circuit obtained by laying strips of metal along the top or
roof of a railway-car, and the installation of a special telegraph
line running parallel with the track and strung on poles of only medium
height. The train, and also each signalling station, was equipped
with regulation telegraph apparatus, such as battery, key, relay, and
sounder, together with induction-coil and condenser. In addition, there
was a special transmitting device in the shape of a musical reed, or
"buzzer." In practice, this buzzer was continuously operated at a speed
of