MINERALOGY. 



Bitumen-.) It is effentially compofed of o-J"" ^"^ '')" 

 JZn, containing lefs carbon than the fohd bitumens or 

 thaf any kind of mineral coal. In Piedmont Perfia Japan 

 and other countries, it is ufed in lamps, m place of od, for 

 iTghtmg ftreets and public buildings; ^^ ^f^^^^^^^J^'^^ 

 earth, and burned for warmmg rooms. In Ava, numerous 

 S are worked for mineral oil or petroleum, the Aafts 

 ^funk through coal ftrata to the coal from whence the 

 oil iffues; it IS intermixed with water, and .s feparated by 



%"macoUTB, Jrf..!.fe of Lin. Chau.arfenlatee, 

 alnv Its colours are fnow-white and mdk-wbte, fome- 

 times inclining to reddifli or yellowifli-white. It occurs in 

 W n!forn° botr^-oidal and globular maffes ; fometm.es it 

 ncrufts other minerals, or is cryftalhzed in mall divergmg 

 caDill-n-V crvftals. Externally, it has a fdky ghmmenng 

 luilreTLernally, it is fhining or gliftening. The ftruaure 

 5s delicately radiated, either ilra.ght, diverging, or ftellular, 

 and fometimes fibrous. It yields to the nail, and is eahly 

 frangible. The fpecific gravity is 2.5. According to 

 Klaproth, the conftituent parts are, 



Lime . - - - 25.00 



Arfenic acid - - - 50-54 



Water . - - - 24.46 



occurs maflive, reniform, botr}'oidal, and incrufting ; it has 

 a flat couchoidal frafture, a fibrous ftrudxure may fome- 

 times be obferved. It contains near 1.8 1 parts of phof- 

 phoric acid united with 68 of copper. 



Phosphate of Mangancfe. See- MAXGANESE-Orfj. 



Phosphorite, Coffimon, and Phosphorite, Earthy. Thefe 

 minerals have been claffed by mineralogifts as varieties of 

 apatite ; but Mr. Jamefon makes phofphorite a diftincl 

 fpecies, which he divides into two fub-fpecies. 



Common Phofphorite, Majfive Apatite, Aikin ; Chc.ux 

 phofphatee tcrreufe, Haiiy ; has generally a yellowifn, green- 

 ifh, or reddiih-white colour ; it occurs maffive, ftalactitic, 

 reniform, and incruiling, alfo cryftallizedin iix-fided tables ; 

 it is opaque, foft, and eafily frangible. The fpecific gra- 

 vity is 2.8 1. When rubbed in an iron mortar, or laid on 

 hot coals, it emits a greenirti light. According to PcUetier, 

 its conftituent parts are, 



According to John, 

 Lime 



Arfenic acid 

 Water 



27.28 

 46.58 

 23.86 



97.72 



There is an earthy variety of pharmacolite, which occurs 

 in thin cruils, and is dull and opaque. Pharmacolite is 

 found in veins in granite, with ores of cobalt and native 



arfenic. 



Phosphate of Copper, Cutvre .phofphatee, Haiiy. Under 

 the ores of copper, one fpecies of this mineral is defcribed, 

 which was the only one then known. Mr. Jamefon makes 

 three fub-fpecies of phofphate of copper ; foliated phofphate 

 of copper, fibrous phofphate of copper, and compaft phof- 

 phate of copper. 



Foliated Phofphate of Copper, Ctiivre phofphatee rhomloidal, 

 Haiiy, has a greyi(h-black colour externally, but internally 

 is emerald-green, verdigris-green, and leek and olive-green. 

 It occurs cryftaUized in oftahedrons, which are fometimes 

 lengthened or cuneiform ; alfo in rhomboids with fmall 

 curvilinear faces ; the edges and angles are fometimes trun- 

 cated. The ftrufture is lamellar, the luftre ihining, between 

 vitreous and pearlv ; it is tranflucent. This ore is infoluble 

 in water, but diffolves without efFervefcence in nitric acid. 

 Before the blow-pipe, it fufes into abrownifli globule, which 

 fpreads on the furface of the charcoal by a continuance of 

 the heat, and acquires a reddifh-grey metallic lullre. The 

 globule on coohng cryftalhzes into three-fided and fix-fided 

 facets. According to Bucholz, it is a compound of copper 

 and phofphoric acid. It has been found in the neighbourhood 

 of Neufotil in Hungary, and at Virneberg, near Rhein- 

 brettenbach, on the Rhine ; at the latter place it occurs 

 with fibrous phofphate of copper ; the latter mineral is found 

 maffive, botryoidal, and in crufts ; it has a divergingly 

 fibrous or radiated ftrufture. 



Compad Phofphate of Copper, Ctiivre phofphatee compade, 

 Haiiy, has the lame localities as the foliated fub-fpecies ; it 



Lime 



Phofphoric acid 

 Silex 



Fluoric acid 

 Muriatic acid 

 Carbonic acid 

 Oxyd of iron 



59.0 



34-0 

 2.0 



2-5 



C.5 



I.O 

 l.O 



100. 



In part of Eftramadura in Spain near Lagrofan, it forms 

 whole beds that alternate with lime-ftone and quartz. 



Earthy Phofphorite confills of dull earthy particles, loofely 

 cohering, and appears to be the preceding mineral in a 

 decompofing ftate, intermixed with earthy matter. We 

 think the charafters and conftituent parts of thefe minerals 

 entitle them to be claffed merely as varieties of apatite. 

 The multiplication of fpecies, where no fufficient fpecific 

 difference exifts, tends to retard the progrefs of ufeful 

 knowledge, and ought not to be unneceffarily introduced. 



Phosphormangak. Phofphate of manganefe. See 

 Manganese. 



Pk'ROLITE, a mineral defcribed by Hanfmann. It is 

 principally compofed of the carbonate of magnefia. Ac- 

 cording to the defcription of Mr. Jamefon, (Mineralogy, 

 vol. ii. p. 537.) its colours are leek-green, mountain-green, 

 or ftraw-ycUow. It occurs maflive ; internally it is dull 

 or glimmering and pearly. The fratture is long, fplintery, 

 which palfes by gradation to flat conchoidal. In fome 

 inftances, it (liews a delicate concentric fibrous ftrufture. 

 It fometimes occurs in concretions which are either con- 

 cealed or have undulating lamelh^. It is tranflucent on the 

 edges, and is rather hard, and difficultly frangible. It feels 

 meagre, and is infufible. The fpecific gravity is 2.53. It 

 appears to be allied to ferpentine and talc. 



Finite. This mineral is nearly allied to mica. It 

 occurs cryftalhzed in regular fix-fided prifms, which, 

 according to Haiiy, is the primitive form. The prifms are 

 fometimes truncated on the edges and angles. Maflive 

 varieties of pinite alfo occur in thick and ftraight lamellar 

 concretions. (See Pinite.) This mineral is found in the 

 granite veins at St. Michael's Mount, Cornwall, and ia 

 iome parts of Scotland in porphyry. 



Pipe-clay. See Clay, and Porcelain Clay, yld- 

 denda. 



Pistacite, or Epidote. See Pisx.^ziTE, and Epidote, 



Addenda. 



Pitch-coal, or JeU See Jet. 



Pitch- 



