Till. .\.\TI\ I. 1. 1. 1. Ml A I- _'S7 



Wyoming. Hut by far the most important deposit, is at Bayou 

 Choupique, Lake ( 'harles, Louisiana, when- a bed of almost purr 

 sulphur 100 feet thick, lies at a depth of 440 feet below tin- -ur- 

 This deposit furnishes nearly all the 350,000 tons annually 

 consumed in the Tinted States, most of which was formerly 

 imported from Sicily. 



I.arjre quantities of sulphur are used in the wood pulp industry; 

 in the manufacture of matches; in blasting powder ; in vulcanising 

 rubber, and in bleaching through the chemical action of SO 2 . 



Artificial crystals may be formed by evaporating a saturated 

 solution of sulphur in carbon disulphide. There are many allo- 

 tropic forms of sulphur; a-sulphur is stable at ordinary tempera- 

 tures, while monoclinic, /3-sulphur, forms when melted sulphur is 

 allowed to cool until a crust forms, which is broken and the still 

 liquid interior is poured off, when crystals of this monoclinic form 

 will cover the walls. On standing they become opaque from 

 the formation of small crystals of the more stable orthorhombic 

 form. 



PLATINUM 



Platinum. Pt ; Isometric ; Type, Ditesseral Central ; Common 

 forms, c (100), o (111), d (110) ; Malleable; Sectile and ductile; 

 H. = 4-4.5; G. = 14-19, when pure, 21.42; Color and streak, 

 steel-gray; Luster, metallic; Opaque. 



B.B. Infusible, fusing point 1755. Soluble in hot aqua regia. 

 For other tests see page 582. 



General description. Crystals are not common, but the cube, 

 octahedron, and rhombic dodecahedron occur. Usually it occurs 

 as fine grains or in irregular rolled masses. Native platinum is 

 always alloyed with other metals of the platinum group, 'as 

 osmium, iridium, paladium, rhodium, and ruthenium, all of which 

 occur only in the native metallic state, with the exception of plati- 

 num, which occurs in sperrylite (PtAsj) as an arsenide, and ruthe- 

 nium in laurite (RuS 2 ) as a sulphide. In addition platinum often 

 contains iron, nickel, and gold, to which its variable specific gravity 

 and hardness are due. 



Deposits of platinum are associated with basic rocks, as serpen- 

 tine and peridotite. Its most constant companion is chromite. 

 Platinum was first discovered in the gold washings of the Pinto 

 Kiver, Colombia, South America, about the year 1720, and in the 



