HYDRO-SULPHURETS. 345 



in an equal bulk of the above named compound of sulphur and al- 

 kali ; the vial being corked and shaken, the peculiar fluid gradually 

 subsides to the bottom, in the form of " a brown, viscid, semi-fluid 

 mass." Henry. The hydrogenized sulphuret of lime is also used, 

 in the same manner, for obtaining this compound. 



3. PROPERTIES. 



(a.) Odor like that of putrid eggs ; heavier than water ; burns 

 with the smell of sulphurous acid. 



(5.) A gentle heat causes sulphuretted hydrogen to exhale, and 

 sulphur only is left. 



(c.) It unites with alkalies and earths, and produces the sulphu- 

 retted hydro-sulphurets, or hydroguretted sulphurets. 



(d.) If kept in a vial, floating on water, it exhales sulphuretted hy- 

 drogen, whenever the stopper is withdrawn. 



(e.) If placed on the tongue, it gives a pungent bitter taste, exhales 

 sulphuretted hydrogen, and leaves sulphur in the mouth. 



4. COMPOSITION. According to Mr. Dalton, 2 proportions of sul- 

 phur =32-f-l of hydrogen =33. In centesimal proportions,* it con- 

 sists of sulphur 96.75, hydrogen 3.25 = 100. Its combinations with 

 alkalies will presently be considered. 



HYDRO-SULPHURETS. f 

 COMPOUNDS OF SULPHURETTED HYDROGEN AND BASES. 



Introductory Remarks. 



It has been already observed, that sulphuretted hydrogen performs 

 the functions of an acid. It is not sour to the taste, but it reddens 

 the infusion of vegetable blue colors, or at least that of litmus or 

 radishes ; its most important character, as an acid, is, that it com- 

 bines with the alkalies and alkaline earths, neutralizing their alkaline 

 properties, and forming crystallizable compounds, analogous to the 

 salts. Some have therefore enrolled sulphuretted hydrogen among 

 the acids, but, in a free state, except a feeble effect upon some of the 

 blue test colors, its properties are so different from those of acids, 

 that I prefer to consider it as merely a compound combustible gas, 

 adding a notice of those properties that assimilate it to acids. { 



1. PREPARATION of hydro sulphurets. Formed, by passing sul- 

 phuretted hydrogen gas through the base, suspended or dissolved in 

 water, in Woulfe's or other convenient apparatus. 



* Henry, Vol. I, p. 447. 



t Called .by some authors hydro-sulphates, but it would seem, unhappily; as the 

 learner is in danger of confounding them with the sulphates: the old name appears 

 to be unexceptionable. See Dr. Turner's Chemistry, 2d ed. p. 603. 



\ It has been called the hydro-thionic, and the hydro-sulphuric acid ; neither 

 name has obtained much currency, and the latter confounds this body with the com- 

 mon sulphuric acid. 



44 



