ciently long in operation to allow us to draw some conclusions as
to the practical results obtained and what is possible in the near
future. The advantages which have been demonstrated on Madison Avenue,
in New York; Dubuque, Iowa; Washington, D.C., and elsewhere, may be
summarized as follows:

_First_. The independent feature of the system. The cars independent
of each other, and free from drawbacks of broken trolley wires;
temporary stoppages at the power station; the grounding of one motor
affecting other motors, and sudden and severe strains upon the
machinery at the power station, such as frequently occur in direct
systems; the absence of all street structures and repairs to the same,
and the loss by grounds and leakages, are also very considerable
advantages, both as to economy and satisfactory operation.

_Second_. The comparatively small space required for the power
station. Each car being provided with two or more sets of batteries,
the same can be charged at a uniform rate without undue strain on the
machinery of the power station, and as it can be done more rapidly
than the discharge required for the operation of the motors, a less
amount of general machinery is necessary for a given amount of work.

Another and important advantage of the system is the low pressure of
the current used to supply the motors, and the consequent increased
durability of the motor, and practically absolute safety to life from
electrical shock.

It has been demonstrated also that the cars can be easily handled in
the street; run at any desired speed, and reversed with far more
safety to the armature of the motor than in the direct system. The
increased weight requires simply more brake leverage.

The modern battery, improved in many of its details during the last
year, is still an unknown quantity as to durability. There is the same
doubt concerning this as there was at the time incandescent lamps were
first introduced. At that time some phenomenal records were made by
lamps grouped with other lamps.

Similarly, some plates appeared to be almost indestructible, while
others, made practically in the same manner, deteriorate within a very
short time. It is, consequently, very difficult to exactly and fairly
place a limit on the life of the positive plates as yet. Speaking
simply from observation of a large number of plates of various kinds,
I am inclined to put the limit at about eight months; though it is
claimed by some of th