Powell

3812

Powet

of Commerce and Labor, to study causes of
European emigration, and in 1907 chief of di-
vision of information, Bureau of Immigra-
tion.

Powell, John Wesley (1834-1902), Am-
erican geologist, was born in Mount Morris,
N. V. He was professor of geology in the Illi-
nois Wcsleyan University (1865-?), and suc-
cessfully explored the Grand Canon of the
Colorado 08GS-q). In i88r he succeeded Clar-
ence King as director of the U. S. Geological
Survey, but was compelled by ill-health to re-
sign the position in 1894. In 1900 he conducted
an exploring expedition to Cuba to study pre-
historic remains there.

Powell, Maud (1868-1020), American vio-
linist, was born in Peru, Til. For 20 years she
devoted herself to concert playing with the
most important orchestras of the country,
taking rank as the foremost woman violinist
of America. In 1892 she accompanied the
Arion Society of New York upon a tour to
Germany, and afterwards made successful pro-
fessional visits to England, Germany, Russia,
Denmark, and South Africa.

Powell, Sir Robert Stephenson Smyth
Baden (1857-1940, British general en-
tered the army in 1876. During the Boer War
(1899) he was in command of the small force
which held Mafeking for 215 days against a
large besieging army, and in recognition of this
accomplishment was promoted major-general,
In 1908 he founded the organization of Boy
Scouts and Girl Guides to promote good citi-
zenship in the rising generation.

Power or Power of Appointment, in
law, an independent authority vested in one
or more persons to alienate or encumber lands
irrespective of the ownership thereof. Such
authority must be derived from the present
or a former owner of the lands subject there-
to, and it may be conferred on the person in
whom an estate in the lands is vested, or, as
is more frequently the case, upon one who has
no interest whatsoever in the lands, Powers
arc frequently employed both in England and
in America to vest a power of sale or devise
in a life tenant, or a power of sale in executors
in the settlement of estates. In several States
of the United States they are wholly regulated
by statute,

Power Development. The supremacy of
the United States in national wealth and pro-
ductive capacity is primarily due to the in-
tensive exploitation of its resources, its labor-
saving machinery, and its sources of power,
Its high scale of production in agriculture,
mining, and manufacturing must, therefore,

be credited in a large measure to the extensive
use of power-driven machinery.

Aside from the attempts to utilize the di-
rect radiation of the sun, the use of the wind-
mill, tide mill, and wave motor, and the re-
cent generation of steam in pipes sunk into
the ground in volcanic regions, the world's
supply of power is dependent upon the
chemical storage of the sun's energy in the
form of coal, oil and natural gas, and wood,
and the potential energy of water impounded
above sea level. Among the latter common
sources of energy the most abundant sup-
ply Is found in the coal deposits. The heat of
combustion of coal, most of which is supplied
by the carbon content, may be utilized to de-
velop steam pressure in a boiler, and the steam
in turn may be made to drive a steam engine
or turbine and produce mechanical power.
Unfortunately, the distribution of the coal de-
posits is not uniform over the United States,
the most extensive area of high-grade coal ex-
isting for the most part east of the Mississippi
River. This fact is intimately connected with
many problems of power development.

In some remote geologic age another form
of organic matter, possibly of the animal king-
dom, became sealed up in 1he crust of the
earth and in the course of time became con-
verted into oil and natural gas. Oil contains
an even greater amount of energy per pound
than coal. It may be burned under boilers to
produce steam for engines or turbines and
possesses the further advantage over coal of
being more easily handled and controlled. By
mixing air with the lighter grades of distilled
oil a combustible gas is formed which may be
exploded by electric ignition in the cylinders
of an internal combustion engine, with high
efficiency. This type of engine as designed for
automobile and airplane service possesses the
important property of developing more power
per unit weight of engine than any other type
of prime mover. The Diesel engine, which is
adapted only to stationary power plants, may
be operated with crude oil or even with the
residue of crudr oil after the lighter constitu-
ents of the oil have been abstracted for other
important purposes.

While the use of Diesel engines on land or
ship power plants not exceeding a few thou-
sand horsepower in capacity is at present de-
sirable in the economic sense, and the internal
combustion engine utilizing gasoline as a fuel
is now unsurpassed for automobile, tractor,
and airplane service, the continued use of oil
in these developments depends seriously upon
the relationship of the supply to the future