116 IIOAV ( ROI'S FKKH. 



is of almost universal occurrence in small quantities. Some 

 forms of it easily oxidize when exposed to air, and furnish 

 the green-vitriol (sulnliatc of protoxide of iron) of com- 

 merce. 



Apatite aii<l Phosphorite. — These names are applied to 

 the native i)hosphate of lime, which is usually combine 

 ■with some chlorine and fluorine, and may besides conta . 

 other ingredients. Apatite exists in considerable quantity 

 at Hammond and Gouverneur, in St. Lawrence Co., X. 

 Y., in beautiful, transparent, green crystals ; at South 

 Burgess, Canada, in green crystals and crystalline masses ; 

 at Hurdstown, N. J., in yellow crystalline masses ; at 

 Krageroe, Norway, in opaque flesh-colored crystals. In 

 minute quantity apatite is of nearly universal distribution. 

 The following analyses exhibit the composition of the 

 principal varieties. 



Kragei'oe, Hurdstown^ 



Norway. New Jersey. 



Yoelcker. J. D. Wliitney. 



Lime, 53.84 53.37 



Phosphoric acid, 41.25 42.23 



Chlorine, 4.10 1.02 



Fluorine,* 1.23 ? ? 



Oxide of iron, 0.29 trace 



Alumina, 0.38 



Potash and soda, 0.17 



Water, 0.42 



Phos[)horite is the usual designation of the non-crysta 

 line varieties. 



Apatite may be regarded as a mixture in indefinite 

 l)roiiortions of two isomorphous compounds, cJilornpatite 

 nud Jlxorapc/tite, neither of which has yet been found jiure 

 in nature, though they have been produced artificially. 



* Flnnriiu" wfi-; not dcterminril in i 

 luiciit arc'calcul;ilud (by Il:iiu;nrl»!)i't 



