ersome series of friction pulleys. Each wheel of the locomotive had
a metal rim and a centre web of wood or papier-mache, and the current
picked up by one set of wheels was carried through contact brushes and
a brass hub to the motor; the circuit back to the track, or other rail,
being closed through the other wheels in a similar manner. The motor had
its field-magnet circuit in permanent connection as a shunt across the
rails, protected by a crude bare copper-wire safety-catch. A switch in
the armature circuit enabled the motorman to reverse the direction of
travel by reversing the current flow through the armature coils.

Things went fairly well for a time on that memorable Thursday afternoon,
when all the laboratory force made high holiday and scrambled for
foothold on the locomotive for a trip; but the friction gearing was
not equal to the sudden strain put upon it during one run and went to
pieces. Some years later, also, Daft again tried friction gear in his
historical experiments on the Manhattan Elevated road, but the results
were attended with no greater success. The next resort of Edison was to
belts, the armature shafting belted to a countershaft on the locomotive
frame, and the countershaft belted to a pulley on the car-axle. The
lever which threw the former friction gear into adjustment was made to
operate an idler pulley for tightening the axle-belt. When the motor
was started, the armature was brought up to full revolution and then the
belt was tightened on the car-axle, compelling motion of the locomotive.
But the belts were liable to slip a great deal in the process, and the
chafing of the belts charred them badly. If that did not happen, and if
the belt was made taut suddenly, the armature burned out--which it
did with disconcerting frequency. The next step was to use a number of
resistance-boxes in series with the armature, so that the locomotive
could start with those in circuit, and then the motorman could bring it
up to speed gradually by cutting one box out after the other. To stop
the locomotive, the armature circuit was opened by the main switch,
stopping the flow of current, and then brakes were applied by long
levers. Matters generally and the motors in particular went much better,
even if the locomotive was so freely festooned with resistance-boxes
all of perceptible weight and occupying much of the limited space. These
details show forcibly and typically the painful steps of advance that
ever