world the doors of a new art and industry. To-day there
are in the United States more than 41,000,000 of these lamps, connected
to existing central-station circuits in active operation.

Such circuits necessarily imply the existence of central stations with
their equipment. Until the beginning of 1882 there were only a few
arc-lighting stations in existence for the limited distribution of
current. At the present time there are over 6000 central stations in
this country for the distribution of electric current for light,
heat, and power, with capital obligations amounting to not less than
$1,000,000,000. Besides the above-named 41,000,000 incandescent lamps
connected to their mains, there are about 500,000 arc lamps and 150,000
motors, using 750,000 horse-power, besides countless fan motors and
electric heating and cooking appliances.

When it is stated that the gross earnings of these central stations
approximate the sum of $225,000,000 yearly, the significant import of
these statistics of an art that came so largely from Edison's laboratory
about thirty years ago will undoubtedly be apparent.

But the above are not by any means all the facts relating to
incandescent electric lighting in the United States, for in addition to
central stations there are upward of 100,000 isolated or private plants
in mills, factories, steamships, hotels, theatres, etc., owned by
the persons or concerns who operate them. These plants represent an
approximate investment of $500,000,000, and the connection of not less
than 25,000,000 incandescent lamps or their equivalent.

Then there are the factories where these incandescent lamps are made,
about forty in number, representing a total investment that may be
approximated at $25,000,000. It is true that many of these factories
are operated by other than the interests which came into control of
the Edison patents (General Electric Company), but the 150,000,000
incandescent electric lamps now annually made are broadly covered in
principle by Edison's fundamental ideas and patents.

It will be noted that these figures are all in round numbers, but they
are believed to be well within the mark, being primarily founded upon
the special reports of the Census Bureau issued in 1902 and 1907, with
the natural increase from that time computed by experts who are in
position to obtain the facts. It would be manifestly impossible to give
exact figures of such a gigantic and swiftly moving industry, wh