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.
(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.
(Py*rom"e*try) n. The art of measuring degrees of heat, or the expansion of bodies by heat.
(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.
(Pyr`o*mor"phous) a. [Pyro- + -morphous.] (Min.) Having the property of crystallizing
by the agency of fire.
(Pyr`o*mu"cate) n. (Chem.) A salt of pyromucic acid.
(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
(Pyr`o*nom"ics) n. [Pyro- + Gr. law.] The science of heat.
(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.
(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.
(Py*roph"a*nous) a. [Pyro- + Gr. to show, pass, to shine.] Rendered transparent by
(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 iron (Chem.), finely reduced iron, which ignites spontaneously on contact with air.
(Pyr`o*phor"ic Py*roph"o*rous) a. [Pyro- + Gr. to bear.] Light- producing; of or pertaining to
(||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.
(Pyr"o*phos"phate) n. (Chem.) A salt of pyrophosphoric acid.
(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
(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.