batteries were used up; the bad showing of the reserve set puzzled
us; every connection was examined and tightened. The wiring of the
carriage was so exposed to the weather that it was found
completely saturated in places with oil and covered with mud. The
rubber insulation had been badly disintegrated wherever oil had
dropped on it. The wires were cleaned as thoroughly as possible
and separated wherever the insulation seemed poor. The loss of
current was probably at the sparking coil; the mud had so covered
the end where the binding parts project as to practically join
them by a wet connection. Cleaning this off and protecting the
binding parts with insulating tape we managed to get on, the spark
being by no means strong, and the reserve battery for some reason
weak.

If we had had a small buzzer, such as is sold for a song at every
electrical store, to say nothing of a pocket voltmeter, we would
have discovered in a moment that the reserve battery contained one
dead cell, the resistance of which made the other cells useless.
At Batavia we tested them out with an ordinary electric bell,
discovering at once the dead cell.

After both batteries are so exhausted that the spark is weak, the
current from both sets can be turned on at the same time in two
ways; by linking the cells in multiples,--that is, side by side,
or in series,--tandem.

The current from cells in multiples is increased in volume but not
in force, and gives a fat spark; the current from cells in series
is doubled in force and gives a long blue hot spark. Both sparks,
if the cells are fresh, will burn the points, though giving much