ACTION OF OXIDES ON ALKALINE HYDUOSULPHURETS. 75 



3dly, That sulphuric acid is never formed. 



4thly, That there are constantly formed water, and sul- 

 phites or sulphuretted sulphites; and frequently metallic 

 swlphurets, 



5thly, That it la consequently im|)Ossible, to obtain the 

 bases of the hydro=uiphure.ts pure by means of metallic 

 oxides. 



Cthly, That, when a sulphuret is dissolved in water, there 

 is never any sulphate formed, as was generally supposed, 

 but sulphites, or sulphuretted sulphites. 



I shall relate some of the i-xpeiiraents, that led me to r>;per'mienti 



these results; and take first as an example the black oxide 



of manganese, and Tcry pure and colourless hydrosulphuret 



of potash. 



As soon as these two substances are mixed, their mutual" '^'^"'^ oxide of 



•111 • c manganese 



action announces itself by a very sensible elevation or tem- and hyrirosul- 



perature ; the hydrosulphuret takes an orange yellow colour, pl>"fft jf 

 like the sulphuretted hydrosulphurets ; and, when muriatic 

 acid is poured in, sulphur is precipitated, and sulphuretted 

 hidrogen evolved. On heating the mixture, it speedily 

 loses its colour, and becomes as limpid as water. At this 

 point the liquid, which is strongly alkaline, precipitates ace- 

 tate of lead of a white colour ; and it might be supposed, 

 that it contained only potash : but, if muriatic acid be pour- 

 ed in, it immediately becomes turbid, sulphur is thrown 

 down, and sclphurous acid gas is evolved. If, after having 

 boiled and filtered, muriate of barytes be added, no precipi- 

 tation takes place. Lastly weak sulphuric acid, poured on 

 well washed oxide of manganese, dissolves cold a large quan- 

 tity, without the evolution of any gas, particularly of sul- 

 phuretted hidrogen. 



Hence it follows, 



1st, That the first effect of the oxide on the hydrosulphu- Results, 

 ret is to convert it to the state of a sulphuretted hydrosul- 

 phuret, acting in this as the air does on hydrosulphurets, 

 and very probably giving rise to a sulphuretted sulphite 

 from the commencement of the process. 



2dly, That a great deal of sulphuretted sulphite is after- 

 ward formed. 



3dly, That no sulphuric acid is produced. 



4thly. 



