Pitch

3744

Pitman

instruments is adjusted by means of a tuning
fork, consisting of two prongs springing out
of a handle, so adjusted as to length that
when struck a particular note is produced

Pitch, the complex mixture of hydrocar-
bons and their derivatives that is either left
when tar, oils, or fatty acids are distilled, or
is found naturally in Trinidad and other
places. Coal-tar pitch, which is typical of
the others, forms about two-thirds of the
tar. Wood-tar pitch is much used in Ameri-
ca for protecting timber from the weather
and the attacks of insects.

Pitchblende, or Uraninite, an impure
uranous uranate, U(UOiK found in the
Erzgebirge, Cornwall, Hungary, and Colo-
rado. It is the only practically available
raw material from which uranium can be
extracted, and this constitutes its chief value.
The radio-activity of pitchblende led to the
discovery that it contained radium, polonium,
and actinium.

Pitcher, Molly (c. 1756-1823), nee Mary
Ludwig, was born in Carlisle, Pa. While be-
sieged in Fort Clinton along with her hus-
band, she is said to have discharged the last
gun against the British. She also distinguished
herself at the Battle of Monmouth (June,
1778). After the battle, covered with blood,
she was presented by General Green to Wash-
ington, who made her a sergeant for her
bravery, and placed her on the list of half-
pay officers for life.

Pitchstone, a glassy igneous rock, dark
green, brown, gray, or almost black in
color. It contains about 5 per cent, of wa-
ter, and is characterized by a somewhat
greasy or resinous lustre.

Pith, or Medulla, the central cellular part
of the stem of a flowering plant. In the
growing condition it is juicy and greenish,
but afterward the protoplasm inside the cells
dies, and the cell sap becomes replaced by
air. The pith then appears pale, dry, and
spongy, as is emphatically shown by the
elder.

Pithecanthropus Erect us. In 1892 Dr.
Dubois discovered, in some fluviatile beds in
the island of Java, the roof of a skull and
a thigh bone. It is probable that the two
bones belong to the same skeleton, and in-
dicate an animal which must have belonged
to a very primitive group of the human race.
They resemble the Neanderthal, Engis, and
Spy skulls. Some doubt remains as to the
age of the betjs in which they were entombed,

for many authorities would assign them to
the Pleistocene period.

Pithecanthropus Erectus.
Profile outline of skull of
Pithecanthropus, A, compared
with outline of skull of Euro-
pean man, u; c, upper surface
(norma verticalis) of skuil of
Pithecanthropus compared with
skull of (D) gibbon (Hylobates
syndactilus]: a, ophryon; 6,
occipital point.

Pithom, one of the store cities which the
Israelites built for Pharaoh in Egypt.

Pitkin, Timothy (1766-1847), American
lawyer and historian, was born in Farming-
ton, Conn. Among his publications are A
Statistical Views of the Commerce of the Uni-
ted States (1816); History of the United
States front 1763 to the Close of Washing-
ton's Administration (2. vols., 1828), long a
standard work.

Pitman, Benn (1822-1910), Anglo-Ameri-
can stenographer and art teacher, brother of
Sir Isaac Pitman, was born in Trowbridge,
Wiltshire, England. He studied in the acad-
emy of his brother, whom he subsequently
assisted in completing his system of phonog-
raphy. He settled in Cincinnati, and there
established the Phonographic Institute, of
which he was president until his death. In
1856 he invented the process for reproducing
relief copper plates of engraved work by gal-
vanic action. He wrote A Plea for American
Decorative Art (1895); Life of Sir Isaac Pit-
man (1902).

Pitman, Sir Isaac (1813-97), inventor of
a system of shorthand, was born in Trow-
bridge, Wiltshire, ffis method of shorthand