275 



. Chemico- Geological Researches on the Sulphurets ivhich are 

 Decomposable by Water. By E. Fkemy. 



The object of this paper, says the Comptes liendus for 

 July 5, 1852, is to make known the production and principal 

 properties of a class of sulphurets, hitherto little examined, 

 and the study of which is alike interesting to chemists and 

 geologists, from the light which it throws on the formation 

 of mineral waters. 



When we consider, says Mr Fremy, the action of water on 

 the sulphurets, we find that these compounds may be divided 

 into three classes : the first comprises the sulphurets of the 

 alkalies and of the alkaline earths which dissolve in water ; the 

 second is formed of the insoluble sulphurets ; the third consists 

 of the sulphurets of boron, silicon, magnesium, and aluminum, 

 which are decomposed by water ; these latter are scarcely 

 known, owing to their preparation having hitherto been acom- 

 panied with great difficulties. In order to a thorough inves- 

 tigation of all the questions which are connected with the de- 

 composition of the sulphurets by water, I first sought for a 

 method by which they might be easily prepared. This method 

 I will now describe. 



It is well known that sulphur exerts no action upon silica, 

 boracic acid, magnesia, and alumina. I imagined it might be 

 possible to replace the oxygen in these substances by sulphur, 

 by the intervention of a second affinity, as that of carbon for 

 oxygen. Such decompositions, produced by two affinities, are 

 not rare in chemistry ; and in some yet unpublished experi- 

 ments on the fluorides, I had observed that the sulphuret of 

 carbon completely decomposed the fluoride of calcium mixed 

 with silica, producing sulphuret of calcium. I was therefore 

 led to presume that the sulphuret of carbon, acting by its 

 two elements upon the preceding oxides, would remove the 

 oxygen, by means of the carbon which it contains, and would, 

 at the same time, form sulphurets ; this supposition I found 

 confirmed by experiment. In fact, I have obtained the sul- 

 phurets of boron, silicon, magnesium, and aluminum, by sub- 

 mitting boracic acid, silica, magnesia, and alumina, to the 



