Procida

3839

Proctor

graphic prints of 'black-and-white' subjects
on paper coated with sensitized gelatin, ink-
ing these prints, and transferring them to the
lithographic stone. In this way much copy-
ing of designs by hand drawing upon the
stone was avoided.

Line-etching.—The last process led natu-
rally to line-etching. Line-etching has dis-
placed every other process for the cheap and
rapid reproduction of designs which do not
contain light and shade. As in photolith-
ography, a light-and-shade effect can be se-
cured, provided that the original itself con-
tains that effect in lines or dots—not in
washes. The line-etching process has now
been improved by printing from the negative
direct on the zinc plate, instead of printing
on paper and transferring to zinc.

The half-tone process faithfully repro-
duces light and shade in a copper block suit-
able for raised printing. The discovery of
'half-tone' is the chief cause of the great in-
crease of illustration in books and magazines.
The printing and the biting of the zinc plate
are the same as in line-etching. Process was
early applied to the production by photo-
graphy and etching of metal surfaces for de-
pressed or intaglio printing. In tnis group of
processes the design must be bitten away in-
stead of being left in relief, so the photo-
graphic printing of the plate must be done
from a positive or reverse negative. A simi-
lar process called rotogravure was brought
out in the United States in 1912. In this
process illustrations with accompanying text
are etched on copper cylinders and printed on
a rotary machine. This prints both sides of
the paper simultaneously at a speed of 3,000
impressions per hour. -This process is used
extensively in newspaper art supplements
and illustrated weeklies.

The latest development has been the in-
vention of three-color process work, by
which fully-colored pictures are placed on
the photographer's screen, and three nega-
tives made through different colored glasses
placed in front of the camera lens. Each of
these negatives is then used for making a
half-tone block, and the three blocks—print-
ed in yellow, red, and blue respectively, one
above the other—produce a faithful repre-
sentation of the original. See Verfasser's
Half-tone Process (sd ed. 1904), Von Hubl's
Three-color Photography, Jenkin's Manual
of Photo-engraving.

Procida, isl., Italy, w. of Gulf of Naples, 2
m. from mainland. It is of volcanic origin.
The capital of same name, also known as

Sancio Cattolico, has a good harbor. The
island was formerly owned by John of Pro-
cida, the chief instigator of the Sicilian
Vespers; p. 14440.

Proclamation. The announcement of some
state matter or law to the public, usually by
the chief executive of a nation, state, or mu-
nicipality. It is generally confined to the
announcement of some executive act, as the
fixing of a day for general thanksgiving. See
STATUTE.

Proclus (412-485), a philosopher of the
Neo -Platonic school, was a native of Con-
stantinople, but spent most of his life at
Athens. In philosophy he attempted to blend
Aristotle's logic with the Neo-Platonic spec-
ulations. The most important of his works
are commentaries on the Timceus and other
works of Plato.

Procne. See Philomela.

Proconsul, in ancient Rome, a consul who
had his power prolonged beyond his
ordinary year of office, which practice
arose in 327 B.C., from the necessity of
keeping several armies in the field and pro-
ionging the command of a victorious general.
A proconsul was supreme in his province,
and carried on war on his own authority.

Procop, Andrew (c. 1380-1434), a Bohe-
mian monk, who went over to the Hussites,
and after the death of Ziska (1424) became
leader of the Taborites, the more fanatical
party of that sect. He wrought great havoc
among the towns and villages of Austria,
Silesia, Saxony, and Franconia, and defeated
several £crusading' imperialist armies that
were sent against him, especially at Taus in

Procrustes, in ancient Greek legend, a rob-
ber of Attica, whose real name was Polype-
mon or Damastes. He invited strangers
to his house, and then forced them into a
bed; if they were too tall for it, he hewed
of! their limbs; if too short, he stretched
them until they died.

Procter, Bryan Waller (1787-1874),
English poet and biographer, born at Leeds.
Procter wrote under the pseudonym 'Barry
Cornwall,' an imperfect anagram of his
name. His Poetical Works have had a wide
circulation in the U. S. as well as in Eng-
land.

Proctor. The name applied to an attorney
in ecclesiastical and admiralty courts in Eng-
land and in admiralty courts in the United
States. See ATTORNEY.

Proctor, Richard Anthony (1837-88),
English astronomer, born in Chelsea, Lon-