102 Progress of Foreign Science. 



hydrogen gas, and without a deposit of sulphur, &c. ; and they 

 are transformed into neutral sulphates by the nitrate of barytes ; 

 but it is not possible to have a proof of this fact in the proportion 

 of oxygen which is disengaged during the reduction, as with the 

 sulphurets of barium, &c, because the sulphurets of potassium 

 and sodium are so fusible and volatile that the greater part pene- 

 trates into the charcoal coating, while the rest is dissipated in 

 vapour. 



We shall content ourselves with one or two examples of Mr. 

 Berthier's experiments. 120 grammes of crystallized sulphate of 

 barytes of Auvergne, reduced to powder, having been heated in 

 a brasqued crucible at the porcelain furnace of Sevres, afforded a 

 mass of sulphuret strongly agglutinated, of a granular crystalline 

 fracture, and a slightly reddish-grey colour. It weighed 86 gram- 

 mes. The loss was therefore 34 grammes — 28 per cent, as in a 

 former experiment. Now the quantity of oxygen contained in the 

 sulphate of barytes being theoretically 28.5 per cent., it is evident 

 that the sulphuret produced by the reduction of this salt is the 

 sulphuret of barium, B.S., which must be composed of 



Barium O.8099 ... 100 



Sulphur 0.1901 . . . 24,47 



The sulphuret of barytes, thus procured, dissolves completely in 

 water, without colouring it. Muriatic acid disengaged sulphuretted 

 hydrogen from the solution without perceptibly disturbing it. 



Compound Sulphurets. — The alkaline sulphurets, and the al- 

 kaline-earthy sulphurets unite very readily together, and with most 

 metallic sulphurets in the dry way. Although this combination 

 can take place nearly in every proportion, the resulting bodies are 

 true combinations and not mere mixtures. In fact, these bodies 

 are perfectly homogeneous, and frequently retain no trace of the 

 physical properties of their components, or at least of one of them. 

 These compound sulphurets are analogous to alloys, and to vi- 

 treous mixtures. 



Sulphate of Potassium and Barium. — 5 gr. of sulphate of pot- 

 ash, and 5 gr. of sulphate of barytes, afforded a button of sul- 

 phuret weighing 5.6 gr. and which consequently must have con- 

 tained Sulphuret of potassium 0.357 



Sulphuret of barium 0.643 



It thence follows that more than the half of the sulphuret of potas- 

 sium, produced from the sulphate of potash, had been volatilized 

 during the operation. 



4. On the acid of the triple Prussiates. By M. Gay Lussac. 



The nature of the acid contained in the combinations distin- 

 guished a short time since by the name of triple prussiates, as 

 also its chemical constitution, appear to me no longer involved 

 in uncertainty. M. Porrett, to whom we owe the important 



