ches manufactured in this country was $12,556,000.
This has increased steadily from $429,000 in 1849. In 1914 the glass
industries in this country made 7,000,000 lamps, 70,000,000 chimneys,
16,300,000 lantern globes, 24,000,000 shades, globes, and other gas
goods. Many millions of other lighting accessories were made, but
unfortunately they are not classified.

Some figures pertaining to public electric light and power stations of
the United States for the years 1907 and 1917 are as follows:

1917 1907
Number of establishments 6,541 4,714
Commercial 4,224 3,462
Municipal 2,317 1,562
Income $526,886,408 $175,642,338
Total horse-power of plants 12,857,998 4,098,188
Steam engines 8,389,389 2,693,273
Internal combustion engines 217,186 55,828
Water-wheels 4,251,423 1,349,087
Kilowatt capacity of generators 9,001,872 2,709,225
Output in millions of kilowatt-hours 25,438 5,863
Motors served (horse-power) 9,216,323 1,649,026
Electric-arc street-lamps served 256,838 ....
Electric-filament street-lamps served 1,389,382 ....

In general, there is a large increase in the various items during the
decade represented. The output of the central stations doubled in the
five years from 1907 to 1912, and doubled again in the next five years
from 1912 to 1917. Street lamps were not reported in 1907, but in 1912
there were 348,643 arc-lamps served by the public companies. The number
of arc-lamps decreased to 256,838 in 1917. On the other hand, there were
681,957 electric filament street lamps served in 1912, which doubled in
number to 1,389,382 in 1917. The cost of construction and equipment of
these central stations totaled more than $3,000,000,000 in 1917.

Although there is no immediate prospect of the failure of the coal and
oil supplies, exhaustion is surely approaching. And as the supplies of
fuel for the production of gas and electricity diminish, the cost of
lighting may advance. The total amount of oil available in the known
oil-fields of thi