PROTRACTOR 



276 



PTEROCARPTJS 



Protractor, (pr5-trak'tor). [L. protraho, I 

 draw forth.] An in- 

 strument used in draw- 

 ing, for the measure- 

 ment of angles. P. 

 muscle: one used to ex- 

 tend the leg, arm, &c. 



Protyl, (pro'til). [Gk. Protractor. 



protos, first ; Injle, material.] A new name 

 for methyl, q.v. 



Protylen, (pro'ti-len). [Protyl, q.v.] = Hy- 

 dride of methyl=Marsh gas, q.v. 



Protylic, (pro-ti'lic). [Protyl, q.v.] A new 

 name for methylic. 



Proustite, (pro-u'stit)=Lij:ht red silver ore: a 

 mineral, chiefly sulphide of silver and 

 arsenic, with hexagonal crystallization. 



Proximate, ( proks'i-mat ). [L. proximatus, 

 near.] P. analysis: the separation of a com- 

 plex substance into its constituent com- 

 pounds. P. principles: organic compounds 

 which are the constituents of more complex 

 organizations. 



Prunus, (pru'nus). [The Latin natne.]= 

 Plum, cherry, apricot, &c.: a plant lelong- 

 ing to Drupacese. P. *pinos=Blackthorn. 



Prussian, P. blue: an hydrated compound 

 of ferrooyanide and irou=Oxalo-nitrile. P. 

 gun, v. Gun. 



Prussiate of potash. Rfd P.=Ferricyanide 

 of potassium. Green P. = Magnetic ferri- 

 cyanide of potassium. 



Prussic acid, (prus'8ik) = HCN=Cyanic hy- 

 dride=Hydrocyanic acid, q.v. A colourless, 

 inflammable, volatile, and very poisonous 

 liquid; named from being obtained from 

 Prussian blue. 



Psalterium, (sawl-te'ri-um). fGk. p$alterion, 

 psaltery.] The 3rd stomach of Ruminantia,?.r. 



Psarama, (sam'ma). [Gk. psammot, sand.] 

 Miirrem-grass : a plant belonging to Gra- 

 minacene. P. arenariu Sea-reed. 



Psaronius, (sa-ro 'ni-us). [Gk. ptaros, 

 speckled.] A tree fern, fossil trunks of 

 which atv found in Lower Permian rocks. 



Pseudo. (sQ'do). [Gk. pseudos, false.] A pre- 

 fix implying resemblance sufficiently close to 

 deceive a casual observer. P. alcohols: have 

 a lower boiling point than true alcohols. P. 

 crinus: an encrinite found in Silurian rocks. 

 P. hcemal: vascular system of Annelida; a 

 system of contractile vessels, but with no 

 heart. P. hearts: contractile cavities in 

 Brachiopoda; v. Heart. P. morphism: 1. 

 In crystals, when a crystal has the form of 

 one mineral with the composition of another, 

 caused by the loss, gain, or exchange of some 

 of the constituents. 2. v. Mimicry. P. 

 tnyrma ants: with large eyes, live in horns 

 of bull's-horn thorn, and hunt singly. P. 

 neuroptera: dragon-flies, may-flies, &c. P. 

 orcin=Erythrite, q.v. P. podia: temporary 

 extensions serving for feet, in Rhizopoda, 

 &c. P. scope: an optical instrument, which 

 gives a deceptive appearance to an object 

 seen through it. P. scorpions : one of 

 Hoeveu's sub-divisions of Arachnids=Cheli- 

 feiidse. 



Psidium, (sid'i-um). [Gk. psidion, pome- 



granate.] A plant, belonging to Myrtaceae, 

 found in tropical America. P. pomiferum= 

 Gu;iva. 



Psilomelane, ( sl-lom'e-lan ). [Gk. psilos, 

 smooth ; melas, black.] An amorphous 

 variety of pyrolusite, chiefly peroxide of 

 manganese; also called Black Hematite. 



Psittacidae, ( sit-tas'i-dg ). [Psittacus, <i.v. ; 

 Gk. eidos, form.] Parrots, &c.: ;i family of 

 monogamous birds, belonging to Scansoics: 

 found in tropics, have strong curved links, 

 are gaily coloured, and vocal organs enabl- 

 ing them to utter articulate sounds. 



Psittacus, (sit'ta-kus). [The Latin name.] 

 Parrot : a bird, the type of Psittacidce ; is 

 able to imitate the human voice. 



Psoralea, (s6-ral'e-a). [Gk. psoralcos, warted. ] 

 Bread-root : a plant, belonging to Legunii- 

 nacere, found in N. America. 



Psychology, (si-kol'o-ji). [Gk. psyche, coul; 

 logos, discourse.] The science of the human 

 mind, and of mental processes generally. 

 v. Science, v. Geogeny. 



Paychrometer, (si-kroui'e-ter). [Gk. psychros, 

 cold ; riietron, measure.] An instrument 

 used in hygrometry: two thermometers, one 

 in air, the other with the bulb in water; the 

 difference of the two is the measurement of 

 the moisture of the air. 



Ptarmigan, (tivr'mi-gau). [Tar,,i<'.c!t<tn, the 

 Gaelic name.] Lago- 

 pus mutus : a bird wi^. Jf^fa-. 

 belonging to Tetrao- 

 nidae. 



Pteraspia, (tr-as'pis). 

 [Gk. pteron, wing ; 

 aspi, shield. ] A fish, 

 fossil remains of 

 which are found in 

 Middle Devonian and 

 in Lower Ludlow; 

 the oldest fossil fish 

 known, v. Ostracostei. 



Pterichthys, (ter-ik'this). [Gk. pteron, wine:: 

 icldliyx, fish.] A fish, with wing-like fins 

 and shelly covering, known by remains found 

 ill Old Red Sandstone, v. Ostracostei. 



Ptarmigan. 



Pterichthys. 

 Pteris, (tei-'is). [Gk. pteron, wing.]=Fern=r 



Bracken, q.v.; named from the wing-like 



fronds. 

 Pterocarpus, ( ter-o-kar'pus ). [Gk. pteron, 



