SULPHUR. ;^17 



also in combination with many metals, as iron, lead, copper, 

 zinc, &c. ; and is extracted in considerable quantity from bi- 

 sulphuret of iron or iron pyrites. Sulphur is classed with 

 oxygen ; and the higher sulphurets resemble peroxides in losing 

 a portion of their sulphur, as we have seen some of the latter 

 jose a portion of their oxygen, when strongly heated. Sulphur 

 is likewise extensively diffused, as a constituent of the sulphuric 

 acid in gypsum and other native sulphates. This element also 

 enters the organic kingdom, being invariably associated in mi- 

 nute quantity with albumen, whether fluid in the egg or solid 

 in the hair. 



Properties. Sulphur is found in commerce in rolls, which 

 are formed by pouring melted sulphur into cylindrical moulds, 

 and also in the form of a fine crystalline powder, the flowers of 

 sulphur, which are obtained by throwing the vapour of sulphur 

 into a close apartment, of which the temperature is below the 

 point of fusion of that substance, and in which the sulphur 

 therefore condenses in the solid form and in minute crystals, 

 just as watery vapour does in the atmosphere below 32, in the 

 form of snow. The purity of the flowers is more to be de- 

 pended upon than that of roll sulphur. Sulphur is insipid, 

 and generally inodorous, but acquires an odour when rubbed ; 

 it is very friable, a roll of it generally emitting a crackling sound, 

 and sometimes breaking, when held in the warm hand. Its 

 specific gravity is 1.98. It fuses at 226, and between that tem- 

 perature and 260 forms a clear liquid of an amber colour. But 

 about 320 it begins to thicken, assumes a reddish tint, and if 

 the heat be continued, becomes so thick that the vessel may be 

 inverted without the sulphur flowing out. This change is not 

 occasioned by an increase of density, for fluid sulphur conti- 

 nues to expand with the temperature. Thrown into water, 

 while in this condition, sulphur forms a mass which remains 

 soft and transparent for some time after it is perfectly cool, 

 and may be drawn into threads which have considerable elas- 

 ticity. From 482 to its boiling point 601, it becomes again 

 more fluid, and if allowed to cool returns through the same 

 conditions, becoming again very fluid, before freezing. Sulphur 

 has considerable volatility, beginning to rise in vapour before it 

 is completely fused. At its boiling point it forms a vapour of 

 an orange colour, and distils over unchanged. The density of 

 this vapour is very considerable, being observed to lie between 



