It is usually constructed so as to register the change which the heat to be measured produces in the
length of some expansible substance, as a metallic rod, or in the intensity of a thermo-electric current.
Pyrometric
(Pyr`o*met"ric Pyr`o*met"ric*al) a. [Cf. F. pyrométrique.] (Physics) Pertaining to, or obtained
by, the pyrometer; as, pyrometrical instruments; pyrometrical measurements.
Pyrometry
(Py*rom"e*try) n. The art of measuring degrees of heat, or the expansion of bodies by heat.
Pyromorphite
(Pyr`o*mor"phite) n. [G. pyromorphit, from Gr. fire + form.] (Min.) Native lead phosphate
with lead chloride, occurring in bright green and brown hexagonal crystals and also massive; — so called
because a fused globule crystallizes in cooling.
Pyromorphous
(Pyr`o*mor"phous) a. [Pyro- + -morphous.] (Min.) Having the property of crystallizing
by the agency of fire.
Pyromucate
(Pyr`o*mu"cate) n. (Chem.) A salt of pyromucic acid.
Pyromucic
(Pyr`o*mu"cic) a. [Pyro- + mucic.] (Chem.) Pertaining to, derived from, or designating,
an acid obtained as a white crystalline substance by the distillation of mucic acid, or by the oxidation of
furfurol.
Pyronomics
(Pyr`o*nom"ics) n. [Pyro- + Gr. law.] The science of heat.
Pyrope
(Pyr"ope) n. [L. pyropus a kind of red bronze, fr. Gr. fire + the eye, face: cf. F. pyrope.] (Min.)
A variety of garnet, of a poppy or blood-red color, frequently with a tinge of orange. It is used as a gem.
See the Note under Garnet.
Pyrophane
(Pyr"o*phane) n. [See Pyrophanous.] (Min.) A mineral which is opaque in its natural state,
but is said to change its color and become transparent by heat.
Pyrophanous
(Py*roph"a*nous) a. [Pyro- + Gr. to show, pass, to shine.] Rendered transparent by
heat.
Pyrophone
(Pyr"o*phone) n. [Pyro- + Gr. sound.] A musical instrument in which the tones are produced
by flames of hydrogen, or illuminating gas, burning in tubes of different sizes and lengths.
Pyrophoric
(Pyr`o*phor"ic Py*roph"o*rous) a. [Pyro- + Gr. to bear.] Light- producing; of or pertaining to
pyrophorus.
Pyrophoric iron (Chem.),
finely reduced iron, which ignites spontaneously on contact with air.
Pyrophorus
(||Py*roph"o*rus) n. [NL. See Pyrophorous.] (Old Chem.) Any one of several substances
or mixtures which phosphoresce or ignite spontaneously on exposure to air, as a heated mixture of alum,
potash, and charcoal, or a mixture of charcoal and finely divided lead.
Pyrophosphate
(Pyr"o*phos"phate) n. (Chem.) A salt of pyrophosphoric acid.
Pyrophosphoric
(Pyr`o*phos*phor"ic) a. [Pyro- + phosphoric.] (Chem.) Pertaining to, or designating,
an acid, H4P2O7, which is obtained as a white crystalline substance. Its salts are obtained by heating
the phosphates.
Pyrophyllite
(Py*roph"yl*lite) n. [Pyro- + Gr. leaf.] (Min.) A mineral, usually of a white or greenish
color and pearly luster, consisting chiefly of the hydrous silicate of alumina.