PEA 



PEC 



PART, LOGICAL. Logically, species 

 are called parts of the genus they come 

 under ; and individuals, parts of the 

 species. Really, the genus is a part of 

 the species ; and the species, of the indi- 

 vidual. 



PA'RTICIPLE. A part of speech said 

 to have derived its name from its ^jar- 

 laTiing of the nature both of the verb and 

 of the noun. Home Tooke calls it a " verb 

 adjective." 



PA'RTICLE [particula, a little part). 

 The term applied by grammarians to 

 those parts of speech which are inde- 

 clinable, and are neither nouns nor verbs, 

 but express the relations, connexions, 

 and modifications of ideas. In this sense, 

 particles comprehend adverbs, conjunc- 

 tions, prepositions, and interjections. 



PARTICULAR PROPOSITION. In 

 Logic, a proposition in which the predi- 

 cate is affirmed or denied of some part 

 only of the subject. 



PARTITE LEAF. In Botany, a leaf 

 is so called when it is parted or divided 

 into a fixed number of segments, which 

 are separated nearly down to the base ; a 

 leaf with two such divisions is said to be 

 bipartite; with three, tripartite; with 

 many, pluripartite, &c. 



PASSERI'NiE {passer, a sparrow). 

 Passerine birds or sparrows ; a family of 

 the Deglubitrices of Macgillivray, differ- 

 ing little from the Emberizinae of that 

 author, except in the form of the bill, 

 and in having the upper mandible broad 

 and concave, instead of being narrow 

 and furnished with a prominent knob. 

 By other writers, the Passerine birds are 

 included in the Fringilladae or Finches, 

 a family of the Insessores or Perchers. 



PATENT YELLOW. A pigment con- 

 sisting of chloride and protoxide of lead ; 

 also called mineral yellow. 



PAVO. The Peacock ; a modern 

 southern constellation, consisting of four- 

 teen stars, and occupying a part of the 

 space situated between Sagittarius and 

 the South Pole. 



PAVO'NIDiE {pavo, the peacock). 

 The Peacock family, the first family of 

 Rasorial birds, in Mr. Swainson's ar- 

 rangement. The term PhasianidcB is 

 adopted by other writers. 



PEA IRON-ORE. The common name 

 of the pisiform variety of argillaceous or 

 clay iron-stone. 



PEA-STONE. Pisiform limestone ; a 

 sub-species of limestone, occurring in 

 round granular concretions. 



PEAK. When the summit of a moun- 

 250 



tain rises with an acclivity more abrupt 

 than the rest of the mountain, it is 

 usually, whether conical or not, called 

 a peak. When very slender pointed 

 rocky protuberances form the summits, 

 they are called by the French aiguilles, 

 or needles, but by us generally peaks. 



PEAR GAGE. An instrument in- 

 vented by Smeaton for measuring the 

 degree of the rarefaction of air, and 

 named from its peculiar form. It is a 

 modification of the air-pump gage. 



PEARL. A spherical concretion 

 formed within the pearl oyster, consist- 

 ing of carbonate of lime and albumen. 

 Sir Everard Home considered that the 

 abortive ova of the animal were the nu- 

 clei upon which the pearls were formed. 



PEARL-ASH. The name of potash 

 when it is calcined, and of a whitish 

 pearly lustre. It is employed in making 

 flint glass, soap, &c. 



PEARL-SINTER. Fiorite. A variety 

 of stalagmitic quartz or quartzsinter, 

 found at Santa-Fiora in Tuscany, &c. 



PEARL-SPAR. Another name for 

 brown-spar or sidero-calcite. It consists 

 of the carbonates of lime and magnesia, 

 with traces of other substances, and oc- 

 curs abundantly in the lead mines in 

 the north of England, &c. 



PEARL-STONE. A sub-species of in- 

 divisible quartz, occurring in large beds 

 in clay, porphyry, and secondary trap- 

 rocks, in Hungary and in Spain. 



PEARL-WHITE. The sub-nitrate of 

 bismuth, formerly called Magistery of 

 bismuth. From the nitric solution of 

 bismuth is procured a powder of a pearly 

 lustre, used by perfumers under the 

 name of pearl powder. 



PEAT or TURF. A carboniferous de- 

 posit formed in the low parts of plains 

 by the gradual decomposition of succes- 

 sive layers of vegetables, burning with 

 flame and grey smoke, and emitting a 

 pungent and somewhat fetid odour. It 

 occurs wherever the soil has been long 

 soaked with water, which has no means 

 of complete evaporation. 



PE'CHBLENDE. An ore of uranium, 

 in which the metal exists in the state of 

 sulphuret. 



PE'CORA (plur. of pecus, cattle). The 

 fifth order of the Mammalia in the sys- 

 tem of Linnaeus, where they are placed 

 between the orders glires and belluce. 



PECTIC ACID (7rnKTt9, a coagulum). 

 A substance obtained from the carrot 

 and other vegetables, so named from its 

 remarkable tendency to gelatinize. 



