SULPHUR. 85 



128. Under what circumstances will carbon monoxide form, and how 

 does it act when inhaled ? 



129. What is destructive distillation, and what gases are generally 

 formed during that process? 



130. Explain the structure and luminosity of flames. 



14. SULPHUR. 



S ji = 32. 



Occurrence in nature. Sulphur is found in the uncombined 

 state in volcanic districts, the chief supply being derived from 

 Sicily. In combination sulphur is widely diffused in the form 

 of sulphates (gypsum, CaS0 4 .2H 2 0), and frequently as sulphides 

 (iron pyrites, FeS 2 , galena, PbS, cinnabar, HgS, etc.). Sulphur 

 also enters into organic compounds, during the decomposition 

 of which sulphur is evolved as sulphuretted hydrogen, which 

 gas is also a constituent of some waters. 



Properties. Sulphur is a yellow, brittle, solid substance, 

 having neither taste nor odor. It is insoluble in water and 

 alcohol, soluble in carbon disulphide, oil of turpentine, and fat 

 oils. Sulphur is polymorphous; it crystallizes, from a solution 

 in bisulphide of carbon, in octahedrons with a rhombic base; 

 when, however, liquefied by heat it crystallizes in six-sided 

 prisms, and is obtained as a brown, amorphous substance by 

 pouring melted sulphur into cold water. 



Sulphur melts at 115 to an amber-colored liquid, which is 

 fluid as water; increasing the heat gradually, it becomes brown 

 and thick, and at about 200 it is so tenacious that it scarcely 

 flows; when heated still further the sulphur again becomes thin 

 and liquid, and, finally, boils at a temperature of about 400. 



In its chemical properties sulphur resembles oxygen, being 

 like this element bivalent, and supporting, when in the form of 

 vapor, the combustion of many substances, especially of metals. 

 Many compounds of oxygen and sulphur show an analogous 

 composition, as, for instance, H 2 and H 2 S, C0 2 and CS 2 , CuO 

 and CuS. 



Crude sulphur is the sulphur obtained from the localities 

 where it is found. It generally contains from 2 to 4 per cent, of 



