Pyrogallic Acid
in chemistry, CHO-CH(OH)3, pyrogallol, an acid, discovered by Scheele. Extensively used in photography as a reducing agent.
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Single-source entries: P (101)
Each of these 21 subjects appears in only one of the 6 encyclopedias on this shelf. None is long enough to carry a page by itself, so they are gathered here by letter. Anything that grows moves out to a page of its own.
Pyrograph
an apparatus for enby means graving on wood or leather of a red-hot metallic point.
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Pyrola
. See Wintergreen
Only in Aiton's Encyclopedia
Pyroligneous Acid
impure acetic acid, obtained by the destructive distillation of wood.
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Pyrolith
or LIQUID MARBLE, a composite, plastic material that so closely resembles marble that no one can detect any difference. It fulfils the requirements of the sculptor as to durability and hardness and forms an imperishable material, easy to work and capable and curve of receiving every delicate line of the clay model. It was discovered by American George Julian Zolnay, an sculptor, the result of years of hard work.
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Pyrolusite
one of the most important of the ores of manganese. Used in preparing oxygen gas, with which it at a red heat; and also in glass parts making.
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Pyrope
in mineralogy, one of the garnet group. Color, a deep-red; transparent. Found associated with serpentines, and in streams in Bohemia. Much used in jewelry.
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Pyrophyllite
a hydrated silicate of alumina, occurring in foliated masses, which split into layers on heating. Crystallizes in the monoclinic system. The color may be either yellow or green, some specimens being almost pure white. It somewhat resembles talc, possessing a soapy feeling, and is used in the manufacture of tailors' chalk and slate pencils. In China and Japan harder small imvarieties are used for making ages. It is found in North Carolina, Georgia, Arkansas, Brazil, Sweden and Urals.
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Pyroscope
an instrument, invented by Leslie, to measure the intensity of heat radiating from a hot body or the frigorific influence of a cold body. The instrument is like a differential thermometer, one ball being covered with ball is naked thick silver-leaf; the other and forms the pyroscope.
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Pyrosoma
the sole genus of Pyrosomidæ, a family of Tunicata, with three species. They are brilliantly phosphorescent, and Péron compared them to small incandescent cylinders of iron.
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Pyrotechny
in the proper sense, the science which teaches the management and application of fires. In the more popular sense, however, the word firechiefly refers to the art of making works. The principal ingredients used are purified saltpeter, sulphur, and charcoal.
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Pyroxene
a name used for a group of minerals of very variable composition and origin, but all of which are referable (like the analogous group of amphiboles) to the same chemical type, under the general formula ROSIO2, where R may represent lime, magnesia, the protoxides of iron and manganese, and sometimes soda, potash, and oxide of zinc. Two or more of these bases are always present, the most frequent being lime, magnesia, and protoxide of iron, lime being always present and in a large percentage.
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Pyroxylic Spirit
WOOD SPIRIT, or WOOD NAPHTHA, a mixture of acetone, methyl-alcohol, acetate of methyl, etc., obtained by the destructive distillation of wood in the manufacture of PYROLIGNEOUS ACID (q. v.). It is of nearly equal value to alcohol in making varnishes, as it dissolves the resins, oils, and other similar substances. It is used in making METHYLATED SPIRIT (q. v.).
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Pyroxylin
a form of nitrocellulose, produced by the action of a mixture of sulphuric and nitric acids, slightly diluted with water, on cotton. Soluble in a mixture of alcohol and ether. This solution, on evaporating, leaves a film of in collodion. Pyroxylin is largely used photography. (See NITROCELLULOSE).
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Pyrrhic
a species of warlike dance, which is said to have been invented by Pyrrhus to grace the funeral of his father Achilles. It was danced by boys in armor, accompanied by the lute or lyre. Also a metrical foot consisting of two short syllables.
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Pyrrho
a celebrated philosopher of Elis, and founder of the sect called Skeptics, or Pyrrhonists, flourished about 340 B. C. He was originally a painter, but afterward became a disciple of Anaxarchus, whom he accompanied to India in the train of Alexander the Great, and while there obtained knowledge doctrines of the Brahmins, Gymnosophistes, Magi, and other eastern sages. On the return of Pyrrho to Greece, the inhabitants of Elea made him their high priest, and the Athenians gave him the rights of citizenship. He died in 288 b. c.
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Pyrus
a genus of Pomaceæ, of Pomeæ, a tribe of Rosaceæ. Fruit two to five celled, with cartilaginous walls. North temperate zone. Known species about 40. Five most familiar are: Pyurus communis, the wild pear, P. malus, the wild or crab apple, P. (Sorbus) torminalis, the wild service, P. (Sorbus) aria, the white beam-tree, and P. (Sorbus) aucuparia, the mountain ash or rowan tree.
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Pythagorean Theorem
the 47th proposition of the first book of Euclid's "Elements," which shows that in any right-angled triangle the square of the hypotenuse is equal to the sum of the squares of the other two sides.
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Pythian Games
one of the four great national festivals of the Greeks, held in the Crissæan plain, near Delphi (anciently called Pytho), said to have been instituted by Apollo after vanquishing the snaky monster, Python, and celebrated in his honor every four years. Originally the contests were restricted to singing, with the accompaniment of cithern playing; but flute playing, athletic contests, horse racing, contests in art and poetry were afterward introduced. PYTHON
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Pythoness
the priestess of the temple of Apollo at Delphi, who delivered oracles of the god; 540-530 b. c. the od; hence, applied to any woman who pretended to foretell coming events.
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Pyx
the sacred vessel used in the Catholic Church to contain the consecrated eucharistic elements which are preserved after consecration, whether for the communion of the sick or for the adoration of the faithful in the churches. The pyx is usually made of some precious metal, and the interior is commonly lined with gold. Q, q, the 17th letter and the 13th consonant of the English alphabet, a consonant having only one sound, that of k or c. The name of the letter is said to be from French queue a tail, the form being that of an O with a tail to it. As an initial, Q represents the Latin Quintus in inscriptions or literature; in geometry, etc., it represents the Latin quod (which), as Q. E. D. quod erat demonstrandum=which was to be shown or proved; Q. E. F. quod erat faciendum which was to be done. As a symbol, Q was formerly used for 500, and with a dash over it, for 500,000.
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