SULPHUB. 95 



Lustre resinous. Transparent to translucent. Brittle. H.= 

 1*5 — 2*5. G.= 2.07. Burns with a blue flame and sulphurous 

 odor. In a closed tube it is wholly volatilized and redeposited 

 on the wall of the tube. 



Native sulphur is either pure, or contaminated with clay or 

 bitumen. It sometimes contains selenium, and has then an 

 crange-yellow color. 



Dijf. It is easily distinguished by its burning with a blue 

 flame, and the sulphur odor then afforded. 



Obs. The great repositories of sulphur are either beds of 

 gypsum and the associate rocks, or the regions of active or ex- 

 tinct volcanoes. In the valley of Noto and Mazzai o in Sicily, 

 at Conil near Cadiz in Spain, Bex in Switzerland, and Cracow 

 in Poland, it occurs in the former situation. Sicily and the 

 neighboring volcanic islands, Vesuvius and the Solfatara in its 

 vicinity, Iceland, Teneriffe, Java, Hawaii, New Zealand, De- 

 ception Island, and most active volcanic regions afford more or 

 less sulphur. The native sulphur of commerce is brought 

 largely from Sicily, where it occurs in beds along the central 

 part of the south coast and to some distance inland. It under- 

 goes rough purification by fusion before exportation, which 

 separates the earth and clay with which it occurs. 



On the Potomac, twenty-five miles above Washington, sul- 

 phur has been found associated with calcite in a gray com- 

 pact limestone ; sparingly about springs where hydrogen sul- 

 phide is evolved, in New York and elsewhere ; in cavities where 

 iron sulphides have decomposed, and in many coal mines; near 

 Borax Lake, in California ; Inferno, Humboldt County, Nevada, 

 abundant. 



The sulphur of commerce is also largely obtained from copper 

 and iron pyrites, it being given off during the roasting of theiie 

 ores. 



Sulphur when cooled from fusion, or above 232° F., crys- 

 tallizes in oblique rhombic prisms. When poured into water 

 at a temperature above 300° F. it acquires the consistency of 

 bo ft wax, and is used to take impressions of gems, medals, etc., 

 which harden as the sulphur cools. The uses of sulphur for 

 gunpowder, bleaching, the manufacture of sulphuric acid, and 

 also in medicines, are well known. Sulphur occurs in various 

 ores as sulphides and sulphates. Among the sulphides are 

 pyrite, an iron sulphide ; pyrrhotite, another iron sulphide ; 

 galena, a lead sulphide, the common ore of lead; chalcopyrite, 

 or yellow copper ore, a copper and iron sulphide; cinnabar, a 

 mercury sulphide ; aryentite, a silver sulphide, etc. 



