348 SULPHURETTED HYDRO-SULPHURETS. 



HYDRO-SULPHURET OF STRONTIA. 



In every respect as the last, only the decomposition of the sul- 

 phate is not so striking. 



HYDRO-SULPHURET OF MAGNESIA. 



1. Formed by passing the gas through the magnesia suspended in 

 water. 



2. It is a feeble and imperfectly characterized compound. 



SULPHURETTED HYDRO-SULPHURETS. * 



General Characters. 



1. Formed, by boiling flowers of sulphur with the base, dissolved 

 or suspended in water. 



1 . Caustic heavy fluids, of a greenish yellow, or brownish color. 



2. Stain the cuticle black, have an acrid taste, and an offensive 

 smell. 



3. Deposit sulphur when kept in close vessels, and become more 

 transparent, and lighter colored. 



4. Absorb oxygen gas, and therefore used in eudiometry. 



5. Sulphuric and muriatic acids throw down sulphur, and evolve 

 sulphuretted hydrogen. 



6. Exposed to the air they are slowly changed into sulphates. 



7. Have a soapy feel. 



8. Sulphuretted hydrogen, passed through them, precipitates the 

 excess of sulphur, and converts them into hydro-sulphurets. 



9. Sulphuretted hydro-sulphurets, are formed also, by digesting 

 a hydro-sulphuret upon sulphur, but they do not throw down sulphur 

 when sulphuretted hydrogen is passed through them.f 



SULPHURETTED HYDRO-SULPHURET OF POTASSA. 



1. Boil sulphur, 1 part, with 3 of the solution of caustic potash, 

 of the common strength. J 



2. Or, decompose the sulphate of potassa, by heating it red hot 

 along with J- of charcoal, in a crucible : dissolve every thing soluble 

 in hot water, and filter ; the theory of these facts will be given farther 

 on. 



* Called also hydrogenized, hydroguretted, and hydrogenated sulphurets, but the 

 name in the text is preferred, because it expresses correctly the composition of these 

 bodies. 



t Aikin, Vol. 2. p. 364. 



t Pearl ashes, water, and sulphur boiled together, produce hydrogenized sulphu- 

 ret of potassa of a very good quality, so that it is not necessary to use caustic potash ; 

 probably sal soda would also answer instead of caustic soda. 



