956 SULPHUR 



sulphur. The furnace most generally used is known as the calcarone, and consists of 

 a circular wall of masonry, within which the ore is piled up. Steam at high pressure 

 has also been applied to the fusion of the sulphur. See a paper by M. Pirckhey, en- 

 titled, ' Des Divers Precedes en usuage en Italie pour 1'Extraction du Soufre de ses 

 Minerals,' Bull. d. 1. Soc. dc Find. Min. 1873. 



According to Signer Parodi, there are now (1874) 250 sulphur mines in Sicily. The 

 ore yields from 15 to 40 per cent, of sulphur, but the extraction is so wasteful that an 

 average of only 14 per cent, is obtained. 



In some places sulphur is obtained from the sulphides of iron and copper. In 

 Saxony and Bohemia, they are introduced into large earthenware pipes, which traverse 

 a furnace-gallery; and the sulphur exhaled flows into pipes filled with cold water on 

 the outside of the furnace: 900 parts of sulphide afford from 100 to 150 parts of 

 sulphur, and a residuum of protosulphide. 



Pyrites, as a bisulphide, consisting of 45'5 parts of iron and 54'5 of sulphur, may, 

 by proper chemical means, be made to give off one-half of its sulphur, or about 27 per 

 cent. 



The great disadvantage in the sulphur prepared from pyrites is, that some of the 

 pyrites contain a large quantity of arsenic, and the sulphur thus obtained from them 

 generally contains sulphide of arsenic, hence the sulphuric acid made from it would 

 contain arsenic, and thus be unfitted for many purposes of the arts ; though a tolerably 

 good sulphuric acid may be made directly from the combustion of pyrites, instead of 

 sulphur, in the lead-chambers. See PYRITES. 



Sulphur occurs in commerce in two different forms, viz. solid, or in powder : the 

 former is generally in sticks, and is called lump, roll, or stick sulphur ; and the latter 

 as sublimed or flowers of sulphur ; and also the kind principally used in medicine, as 

 precipitated sulphur or milk of sulphur. These different forms are caused by the 

 different modes of preparation ; if the sulphur be sublimed into large chambers, 

 which are kept cool during the operation, the product will appear as a powder 

 (sublimed or flowers of sulphur) ; but if the chamber be allowed to get hot, the sulphur 

 melts, and Is run off into moulds, and forms the lump sulphur. The washing of the 

 sublimed sulphur is to remove any sulphurous or sulphuric acid, which it generally 

 contains when taken from the chamber. The precipitated sulphur is formed by boiling 

 ordinary sulphur with lime and water ; the sulphur enters into combination with the 

 lime, forming a sulphide of calcium and hyposulphite of lime, which dissolve in the 

 water ; to the filtered liquid hydrochloric acid is added, which unites with the lime 

 and precipitates the sulphur. The sulphur thus precipitated is of a pale yellow colour, 

 and when first precipitated will pass through a filter with the water, just as if it were 

 in solution, from the fact of its being so finely divided. Some manufacturers use 

 sulphuric acid instead of hydrochloric acid in this process, and .therefore the milk of 

 sulphur found in the shops is generally largely contaminated with sulphate of lime, 

 feels gritty between the teeth, and sparkles when looked at in one direction. 



Ordinary sulphur may be crystalline or amorphous ; it is capable of crystallising in 

 two different forms, and is hence said to be dimorphous. One form is that of acute 

 rhombic octahedrons, belonging to the prismatic system, which is the principal form 

 assumed by native sulphur, and may be obtained artificially by the spontaneous 

 evaporation of a solution of sulphur in bisulphide of carbon ; the second form is that 

 of acute rhombic prisms, belonging to the oblique system, which is obtained by fusing 

 sulphur in a crucible, and, when partly cooled, breaking the crust which is formed on 

 the top, and pouring out the part which still remains liquid, when the part which has 

 become solid will remain in long crystals. These crystals differ not only in shape, but 

 also in specific gravity ; the octahedral crystals having a specific gravity of 2'045, 

 and the prisms a specific gravity of 1'982. The red tint, so common in the crystals 

 of Sicily, and of volcanic districts, has been ascribed by some mineralogists to the 

 presence of realgar, and by others to iron ; but Stromeyer has found the sublimed 

 orange-red sulphur of Vulcano, one of the Lipari Islands, to result from a natural 

 combination of sulphur and selenium. 



Sulphur also presents another peculiarity. At all ordinary temperatures it is solid, 

 but it melts at 232 Fahr., and at this temperature it is as fluid as water; if the heat 

 be now gradually raised, it will become thicker and thicker until, between 430 and 

 480 Fahr., it is so tenacious that the vessel containing it may be inverted for a 

 moment without losing ,-iny of its contents ; if while in this state it is cooled suddenly, 

 as by pouring it into cold water it will remain for many hours perfectly soft ami 

 flexible, and may be drawn out into threads ; it now presents none of the appearances 

 of sulphur, and is called amorphous sulphur. After some time, however, it regains its 

 former properties, becoming brittle and crystalline, and mny bo restored still moro 

 rapidly to its original state by melting and slow cooling. If the temperature be Mill 

 raised above 480 Fuhr., the sulphur between this and the boiling-point 792 Fahr., 



