On American Phosphate of Lime. 



255 



it dissolves slowly, without effervescence. Some varieties are 

 phosphorescent. 



(4) Varieties. 



Mineral phosphate of lime was termed apatite by Werner, from a Greek 

 word signifying " deceptive," in allusion to the mistakes made by the older 

 mineralogists with regard to the nature of its many varieties. It is also 

 known by the terms: spargelstein, asparagus-stone, phosphorite, moroxite, 

 chrysolite, eupyrchroite, augustite, and pseudo-apatite. The variety 

 known as talc-apatite, from chlorite slate in Schischimskian Mountains, 

 near Slatoust, contains in 100 parts — lime, 37*50; magnesia, 7'74; phos- 

 phoric acid, 39-02; sulphuric acid, 2*10; chlorine, 0*91; oxide of iron, 

 1*00 ; fluorine, insoluble matter, and loss, 11 '73. Francolite is an apatite 

 from near Tavistock, in Devonshire. It occurs in small masses of irregular 

 aggregated crystals, having a somewhat mammillated surface. According 

 to the analysis of T. H. Henry, 100 parts are composed of — ^lime, 53*38; 

 iron and manganese, 2 "96; phosphoric acid, 41 '34; fluorine and 

 loss, 2-32. 



Professor Jameson gives in the article Mineralogy, in Brewster's 

 Encyclopaedia (pages 484-5), an interesting statement of the 

 varieties of apatite, their localities of occurrence, and respective 

 chemical composition. We have only space on this occasion to 

 glance at a few points selected from that article. 



1. Foliated apatite (common variety) occurs in tinstone veins, and also 

 embedded in talc. It is found in Europe, in yellow foliated talc ; and 

 along with fluor-spar, in the mine called Stena-Gwyn, in St. Stephen's, in 

 Cornwall; and at St. Michael's Mount, Godolphin-bal, in Breage, in the 

 same county ; also in various districts on the continent. In America it 

 occurs in grains or hexahedral prisms in granite, near Baltimore, in Mary- 

 land ; in granite and gneiss, along with beryl, garnet, and schorl, at 

 Germantown, in Pennsylvania ; in iron pyrites at St. Anthony's Nose, 

 in the Hudson, in New York ; in granite at Milford Mills, near Newhaven, 

 in Connecticut ; and at Topsham, in Maine, in granite. Klaproth found 

 it to consist of lime 55, and phosphoric acid 45, with a trace of man- 

 ganese. 



2. Conchoidal apatite (asparagus variety) occurs imbedded in gneiss, 

 near Kincardine, in Ross-shire ; also in beds of magnetic ironstone, along 

 with sphene, calcareous spar, hornblende, quartz, and augite, at Arendal, 

 in Norway. In America it is found embedded in granite at Baltimore ; 

 in gneiss at Germantown, and in mica-slate in West Greenland. Klap- 

 roth ascertained the composition of two specimens of this variety : one 

 from Zillerthal being almost pure phosphate of lime ; while another, from 

 Uto, contained only 92 per cent, of that substance, with 6 per cent, of 

 chalk, 1 of silica, and a trace of manganese. 



3. Common Phosphorite. — Occurs in crusts, and crystallised, along with 

 apatite and quartz, at Schlackenwald in Bohemia, but most abundantly 

 near Leigrosan in the province of Estremadura in Spain, where it is 

 sometimes associated with apatite, and forms whole beds, that alternate 

 with limestone and quartz. Pelletier found 100 parts to consist of — hme, 

 59*0; phosphoric acid, 34*0; silica, 2'0; fluoric acid, 2-5; muriatic 

 acid, 0-5; carbonic acid, 1-0; oxide of iron, I'O. 



4. Earthy Phosphorite. — Occurs in a vein, in the district of Marmarosch 

 in Hungary. Klaproth gives its composition as — lime, 47'CO ; phosphoric 

 acid, 32-25; fluoric acid, 2*50 ; silica, 0-50; oxide of iron, 0*75; water, 

 I'OO ; quartz and loam, 11*50. 



