PYRIDINE 



279 



QUADRANT 



fire; Heliometer, q.v.} An apparatus for 



measuring the quantity of the sun's heat 



received upon the surface of the earth. 



Pyridine, (pir'i-din). [Gk. pyr, fire.]=C 5 H 5 N\ 

 a colourless pungent oil, the type of the 

 pyridine bases. 



Pyridine series of organic bases=CnH 2n -5N : 

 a variety of nitrile bases, corresponding to 

 ammonia, in which the ammonia has been 

 displaced by a triad hydrocarbon ; includes 



pyridiue, picoline, &c. obtained from coal tar. 



Pyriform, ( pii-'i-form ). [L. pyrus, pear; 

 forma, shape.]=Tapering: pear-shaped. 



Pyrites, (pi-ri'tez). [L. pyrites, flint.] A 

 mineral of the iron group, chiefly di-sul- 

 phide of iron, FeSo, crystallising in cubes: 

 used for its sulphur. Arsenical P.=Mis- 

 pickel. Copper P. = Sulphuiet of copper 

 andiron. White P.=Marcasite. 



Pyro-, (pir'o). [Gk. pyr, fire.] A prefix im- 

 plying some relation to fire. 



Pyrocatechm=C 6 H 6 O 2 :=Oxyphenic acid, q.v. : 

 obtained from catechin. 



Pyrochlore, (pir'o-klor). [Gk. pyr, fire.]?= 

 Fluochlore: a mineral, chiefly titanate of 

 calcium. 



Pyrochroa, ( pir-6-kro'a ). [Gk. pyr, fire; 

 c/iroa, colour.] Cardinal beetle: an insect 

 belonging to Coleoptera. 



Pyro-citric, (pir-o-sit'rik). [Pyro and Citric, 

 q.v.] P. acid obtained by heating citric acid. 



Pyro-electricity. Electricity excited by heat, 

 as when tourmaline becomes electric by 

 being warmed between 10 and 150 C. 



Pyro-gallm, (pir-6-gal'lin). [Pyro and Gallic, 

 g.i7.]=Pyrogallic acid=C6H(j(>}: a crystalline 

 substance obtained from gallic acid by the 

 action of heat. 



Pyroheliometer, (pir-o-he-li-om'e-ter). [Pyro 

 and Heliometer, g.v.].=Pyrheliometer, q.v. 



Pyrola, (pi'ro-la). [L. pyrus, pear. ]= Winter- 

 green: an herb, the type of Pyrolacese, named 

 from the leaves resembling that of the pear 

 tree. 



Pyrolacese, ( pi-ro-lu'se-e ). [Pyrola, 9.1?.] = 

 Winter-greens: herbs belonging to Ericales. 



Pyroligneous acid, (pir-5-lig'ne-us). [Gk. pyr, 

 lire; lignum, wood.] Impure acetic acid. 



Pyrolusite, (pir-6-lo'sit). [Gk. pyr, fire; lysis, 

 decomposition.]=MnO2'. native black oxide 

 of manganese : a friable metallic mineral, 

 much used in chemical processes; belongs to 

 the manganese group. 



Pyrometer, ( pir-om'e-ter ). [Gk. pyr, fire; 

 melroii) measure.] An instrument for mea- 

 suring the temperature of furnaces, &c. 

 Daniell's P., v. Daniell's. Jlouldsworth's P. , 

 a modification of Daniell's. Wedgewood's P., 

 by contraction of baked clay. 



Pyromorphite, (pir-o-mor'flt) = Chlorophos- 



phate of lead, one of the ores of lead. 



Pyrope, (pir'op). [Gk. pyropos, fire-faced.] 



Fire-garnet: a variety of garnet. 



Pyrophorus, ( pir-of'6-rus ). [Gk. pyr, fire; 



phoreo, I bear.] Any substance which burns 



spontaneously in air. 



Pyrophyllite, ( pir-o-fil'it ). [Gk. pyr, fire; 



pkyllon, leaf.] A variety of talc, chiefly sili- 

 cate of aluminium. 



Pyrorthite, (pir'or-thit). [Gk. pyr, fire.] A 

 mineral, chiefly hydrated silicate of cerium. 



Pyrosoma, (pir-os-6'ma). [Gk. pyr, fire; soma, 

 body.] A phosphorescent aggregation of bot- 

 rylli, found in some compound ascidians. 



Pyrostilpnite, (pir-o-stilp'nlt) = Feuerbleude 

 = Fire-blende: a mineral. 



Pyrotechny, ( pir-5-tek'ni ). [Gk. pyr, fire; 

 techne, art.] Generally, the application of 

 fire to the arts ; specially, the art of making 

 fireworks. 



Pyroxanthin, ( pir-oks-an'thin ). [Gk. pyr, 

 fire; xanthos, yellow.] =C 2 iH 18 O4: a yellow 

 crystalline substance obtained from wood- 

 spirit. 



Pyroxene, (pir'ok-sen). [Gk. pyr, fire; xenon, 

 stranger.]=Augite: a mineral, chiefly silicate 

 of calcium, magnesium, and iron. 



Pyroxylic, P. spirit =Methyl hydrate=Wood 

 spirit. 



Pyroxylin, ( pir-oks'i-lin ). [Gk. pyr, fire; 

 xylon, wood.]=Gun-cotton: cotton that has 

 been immersed in nitric acid and so oxidised: 

 has properties of combustion aud explosion 



' resembling those of gunpowder. 



Pyrrhoeoris=Scarlet bug. 



Pyrrhosai P. tingens , gives mace. 



Pyrrhula, (pir'u-la)=Bullfinch, q.v. 



Pyrrol, (p!r'rol)=C4H5N : an oily substance 

 obtained from Dippel's oil. 



Pyrus, (pi'rus). [The Latin name.] Pear, apple, 

 &c. : a plant belonging to Pomacese. P. 

 aucuparia=Hoa.n tree. P. aria=.Beam tree. 

 P. e9mimtttu=Pear. P. malus=Apvle. 



Pythagorean, ( pith-a-go-re'an ). P. bean= 

 Nelumbium speciosum. 



Python, (pi'thon). [The Latin name.] = 

 Coluber javanicus; v. Pythons. 



Pythons, (pi'thonz). Large snakes, belonging 

 to Colubridse, found in New World. 



Pythonidse, (pi-thon'i-de). [Python, q. v.; Gk. 

 cidos, form.] Large snakes, of which the 

 python is the type. 



Pyx, (piks). [Pyxis, the Latin word.] A gene- 

 ral term for a box containing any valuable; 

 especially for the box containing sample 

 coins of a new coinage. 



Pyxidium, (piks-id'i-um). [L. pyxis, box.] A 

 dry dehiscent fruit with a kind of lid. 



Q. 



Quadrangle, (kwod-rang'gl). [Quadrangulus, 

 the Latin word.] A plane surface enclosed 

 by four straight lines: specially used as= 

 rectangle; also for a four cornered court, 

 surrounded by buildings. 



Quadrans Muralis, (kwod'ranz mu-ril'lis.) 

 [The Latin name.]=The Mural Quadrant, 

 a northern constellation of small stars only. 



Quadrant, (kwod'rant). [L. quadrans, fourth 

 part.] 1. The quarter of a circle. 2. v. Sex- 



