Popinjay

3789

Population

an improved form, is extensively u?ed. In!
1872 Pope invented the rail circuit for auto-
ma tically controlling the electric-block sig-
nal system in use on American railroads. He
also made many valuable improvements in
telegraphy, and was one of the pioneer patent
attorneys in America, making a specialty of
electrical inventions. In iSS6 he was elected
president of the American Institute of Elec-
trical Engineers.

Popinjay, originally a parrot; then a mark
like a parrot, put on a pole to be shot at by
archers as a test of skill.

Poplar. Trees of the genus Populus (Sal-
icaceas). They usually have broad, alternate
leaves, generally tremulous, and often with
laterally flattened leaf-stalks. The poplars
grow rapidly, and, as in the case of the Lom-
bardy poplar (P. dilatata), with its narrowly
pyramidal head, are picturesque at times.
The cottonwood (P. deltoides) is common
along the watercourses of the West, and
forms a large, picturesque, rapidly growing
tree; another familiar tree in the West, which
turns to pale gold in fall, is the 'quaking asp'
(P. tremuloides], an aspen with similar,
smaller leaves. It springs up quickly in clear-
ings, and holds the soil on mountain sides
until other trees are well started. In the
East the awkward, brittle poplar of wood-
lands is P. grandidentata, having large,
coarsely toothed leaves, a pale-colored trunk
of rapid growth, and quickly rotting wood.

Poplin, a mixed material of silk and wor-
sted, introduced into Great Britain by the
refugees who fled from France on the revo-
cation (1685) of the Edict of Nantes, and
ever since it has been a peculiarly distinct
Irish industry. Many poplins now made have
not a particle of silk in their composition,
but are woven of worsted and flax or wor-
sted and cotton.

Popocatepetl ('smoking mountain'), a vol-
cano in Mexico, between the valleys of Mex-
ico and Puebla, 45 m. s.e. of the former city.
No considerable eruption has occurred since
1548, although minor eruptions took place
in 1802, and the crater still emits smoke and
ashes. Snow covers the summit (17,783 ft.
above sea level), below which are forests of
pine and oak. Sulphur of great purity and in
large quantities is obtained from its crater.

Poppy (Papavcr), a genus of plants, al-
most all with showy red, white, or yellow
flowers, and all valuable as annual or peren-
nial garden plants. The common corn poppy
is P. Rh&as; and of it numerous varieties are
Cultivated in gardens, such as the Shirley, car-

nation-flowered, rjnd ranunculus-flowered
poppies. The Oriental poppies are among the
the showiest of hardy perennial plants. P.
wmnifcntm, a tall annual plant with glaucous
foliage, is the source from which opium is
obtained.

Poppy.

i, Ripe capsule; 2, section;
3, seed; 4, section.

Popular Sovereignty, or Squatter Sov-
ereignty, is a term applied in the -United
States before the Civil War to the doctrine
that each Territory should be left free to de-
cide for itself whether or not slavery was to
be permitted within its limits. The doctrine
seems to have been first enunciated by Lewis
Cass in 1847 J but Stephen A. Douglas was it?
most aggressive and conspicuous advocate,
and it was the basis of the famous Kansas-Ne-
braska Bill of 1854. In 1857 the U. S. Supreme
Court, in the Dred Scott decision, declared
that neither Congress nor Territorial legisla-
tures had power to exclude slavery from the
Territories. See SLAVERY.

Population, the number of people in' any
particular country or community. A study oi
population figures seems to indicate that under
normal conditions the population of a com-
munity should increase steadily; but a station-
ary population may signify increased thrift
and a higher standard of comfort, with a rela-
tively large proportion of the people distrjbu.-