vicissitudes of the plant to which it, belonged, it
continued in active use until 1899--seventeen years.

Edison was from the first deeply impressed with the possibilities of
water-power, and, as this incident shows, was prompt to seize such a
very early opportunity. But his attention was in reality concentrated
closely on the supply of great centres of population, a task which
he then felt might well occupy his lifetime; and except in regard to
furnishing isolated plants he did not pursue further the development of
hydro-electric stations. That was left to others, and to the application
of the alternating current, which has enabled engineers to harness
remote powers, and, within thoroughly economical limits, transmit
thousands of horse-power as much as two hundred miles at pressures
of 80,000 and 100,000 volts. Owing to his insistence on low pressure,
direct current for use in densely populated districts, as the only safe
and truly universal, profitable way of delivering electrical energy to
the consumers, Edison has been frequently spoken of as an opponent
of the alternating current. This does him an injustice. At the time
a measure was before the Virginia legislature, in 1890, to limit the
permissible pressures of current so as to render it safe, he said: "You
want to allow high pressure wherever the conditions are such that by
no possible accident could that pressure get into the houses of
the consumers; you want to give them all the latitude you can." In
explaining this he added: "Suppose you want to take the falls down at
Richmond, and want to put up a water-power? Why, if we erect a station
at the falls, it is a great economy to get it up to the city. By digging
a cheap trench and putting in an insulated cable, and connecting such
station with the central part of Richmond, having the end of the cable
come up into the station from the earth and there connected with motors,
the power of the falls would be transmitted to these motors. If now the
motors were made to run dynamos conveying low-pressure currents to the
public, there is no possible way whereby this high-pressure current
could get to the public." In other words, Edison made the sharp
fundamental distinction between high pressure alternating current for
transmission and low pressure direct current for distribution; and this
is exactly the practice that has been adopted in all the great cities
of the country to-day. There seems no good reason for believing