352 SULPHURETS. 



perature pen elevee, qui n'atteigne jamais la chaleur rouge, ce corps 

 se combine avec les alcalis sans les decomposer, et forme des sul- 

 fures d' oxide." This appears to me so probable, that I shall here 

 preserve a notice of what were, heretofore, regarded as alkaline 

 sulphurets. 



1 . Formed by fusion of sulphur with the base, or decomposition 

 of a sulphate by ignition with charcoal powder.' 54 ' 



2. Of a liver\ color, if formed with caustic alkalies, or greenish 

 yellow, if with their carbonates. 



3. Inodorous, ivhile dry. 



4. Decomposed by a higher degree of heat than that by which 

 they were formed, sulphur being sublimed, and the base left in the 

 bottom of the vessel. 



Chemists and physiciansj were accustomed to use these prepara- 

 tions in solution, but they then ceased to be true sulphurets ; for sul- 

 phuretted hydrogen was generated, and they passed to a new condi- 

 tion ; that of the sulphuretted hydro-sulphurets. In making the 

 preparations, it is of little importance whether we boil the base and 

 sulphur together, or melt them together, and then dissolve them ; or 

 whether we dissolve, in hot water, the residuum from the decomposi- 

 tion of the sulphates, by ignition with charcoal ; for, in either case, 

 by the decomposition of water, we obtain a compound containing 

 sulphuretted or bi-sulphuretted hydrogen ; it is fetid, and acrid, and 

 liberates by the action of acids, precipitated sulphur and sulphuret- 

 ted hydrogen gas. In all these cases also there is a generation, 

 probably from the oxygen^ of the water, of some of the acids of sul- 

 phur, and by spontaneous decomposition, especially if the solution is 

 kept in loosely stopped vessels, the substances pass to the condition 

 of sulphite or sulphate, || and thus lose their peculiar properties. 



II. Sulphurets of the metallic bases of the fixed alkalies and alka- 

 line earths. 



* In the latter case they were left in mixture with the charcoal, and could scarce- 

 ly be exhibited pure ; it now appears that a metallic sulphuret is produced in this 

 manner. 



t Therefore called, in the old language of chemistry, hepar sulphuris or liver of 

 sulphur. 



t Physicians prepare the sulphuret of potash by taking flowers of sulphur and 

 potash or pearl ashes, equal quantities ; they are melted in a covered crucible or 

 skillet, and then kept in a close vessel, but are dissolved for use, in the proportion 

 of two drams in a pint of rain water, and this is used as an external wash. A. table 

 spoonful is taken for a dose, twice in a day ; used for a variety of eruptions, scald head, 

 psora, &c. In pulmonary consumption it may be given, in the above manner or in 

 form of pills, from two to live grains for a dose, repeated two or three times in a day. 

 It removes or diminishes the hectic fever: it has been used internally as an antidote 

 against metallic poisons and to check excessive salivations from mercury. Coni'd. 



Vauquelin supposed from the oxygen of the alkali. 



Jl The preparation from the decomposed sulphate of baryta, is particularly re- 

 markable for passing back to the condition of sulphate, and it often presents distinct 

 prismatic crytals. 



