Chap'. 39.] Natural Hiftory of Sulphur. 257 



fleams of other volatile fubftanees which rife and are 

 condenfed with it. It is purified by being melted in a 

 ladle, and kept in that flate till the impurities fettle at 

 the bottom. If it is an object to obtain fulphur of the 

 greateft purity, this -mud be effected by fublimation ; 

 and in this flate it is commonly fold under the name 

 of flowers of brimflone. Even thefe, however, are 

 fometimes rendered impure by the fulphur taking 

 fire, which produces a mixture of vitriolic acid. This 

 is effectually removed by boiling the flowers in water, 

 which diflblves the acid, and leaves the fulphur in a 

 pure and mild flate. 



Sulphur is fometimes found, more or lefs pure, in 

 the neighbourhood of volcanos, in which cafe it feems 

 to have been feparated, by fubterraneous heat, from 

 fome fubflance with which it was previoufly com- 

 bined. 



The method of burning fulphur for the preparation 

 'of the vitriolic acid has already been defcribed when 

 treating of that acid. 



Sulphur has no action on filiceous earths, but very 

 readily unites with the calcareous. It is alfo capable 

 of combination with magnefia, ponderous earth, and 

 volatile alkali. It unites, however, with much more 

 violence with the fixed alkalies. All thefe combina- 

 tions are of a liver colour, and are therefore called 

 livers of fulphur. By M. Lavoifier they are much 

 more properly denominated fulphurets of thefe feveral 

 fubftanees, as fulphuret of lime, fulphuret of magnefia, 

 &c. Thefe fubftanees are foluble in water, and have 

 confiderable action on feveral other bodies. The 

 combinations of fulphur with earths and alkalies may 

 be all decompofed by means of acids, and the earthy 

 fulphurets by means of the fixed alkalies. Thefe fub- 

 ilances, when diflblved in water, difengage a peculiar 



VOL. II. S gus 



