On Sulphurets. 101 



metallic bases of the earths and alkalies, with sulphur. M. Ber- 

 thier seems, however, to be unacquainted with the researches of the 

 indefatigable Swede, for he says that his experiments have enabled 

 him to resolve the hitherto undecided question, whether the alkalies 

 and alkaline earths exist in the metallic state, in their sulphurets 

 prepared in the dry way. It must be confessed that these experi- 

 ments are so simple and convincing-, as to excite surprise at their 

 not having been sooner made. 



Instead of mixing- the sulphates and charcoal together in the 

 state of powder, whereby after their ignition in a crucible, only 

 impure sulphurets are obtained, M. Berthier finds that perfectly 

 pure sulphurets may be procured, by heating the sulphates in cru- 

 cibles lined with charcoal, (creusels brasqucs de charbon.) This re- 

 sult is derived from the property which the sulphates possess, as 

 well as most oxides, of being reduced by the mode of cementation, 

 when they are kept exposed for a sufficient time, to a proper de- 

 gree of heat in contact with charcoal. The reduction may always 

 be completed in a few hours, by employing a white heat, even 

 though several hundred grammes be operated on, provided the 

 sulphuret be fusible. In other cases, smaller quantities must be 

 taken, and a longer heat applied. The crucible must be filled up 

 with charcoal powder, and closely covered with clay. 



If sulphate of barytes, sulphate of strontites, or sulphate of 

 lime perfectly pure, and previously calcined, be heated in a 

 brasqued crucible, (one lined with solid charcoal,) to the tempera- 

 ture of an iron-ore assay, the resulting sulphuret forms a well ag- 

 glomerated mass, which may be withdrawn from the crucible 

 without breakrng it, by the dexterous application of a knife blade ; 

 and by taking the weight of the sulphuret, it is found that the loss 

 suffered by the sulphate is precisely equal to the weight represent- 

 ing the quantity of oxygen contained in its base and ils acid. If, 

 on the other hand, the sulphuret be dissolved in muriatic acid, we 

 shall ascertain that dining the solution, nothing but perfectly pure 

 sulphuretted hydrogen is disengaged, and that there is formed no 

 deposit of sulphur, nor oxygen-acid having this combustible as a 

 base. Finally, if we heat a portion of the sulphuret in a silver 

 crucible, along with three or four times its weight of nitre, we 

 shall regenerate exactly the quantity of sulphate corresponding to 

 the portion of sulphuret employed, and that the regenerated sul- 

 phate, contains no excess, either of base or of acid. These three 

 experiments concur in proving, in the most evident manner, that 

 the sulphurets produced from the sulphates of barytes, strontites, 

 and lime, contain no oxygen, and consequently that their bases 

 in the metallic state. 



The sulphurets, obtained on reducing the sulphates of potash 

 and soda by charcoal, are equally in the metallic state ; for they 

 dissolve in the acids with the disengagement of pure sulphuretted 



