the Decomposition of the Earths, &c. 1 99 



Viderable period under naphtha. In a length of time, how- 

 ever, they became covered with a wVite crust under this 

 fluid. When exposed to air, a very few minutes only were 

 required for the oxygenation of the bases of the earths. In 

 water the amalgam of barytes was most rapidly decomposed v 

 that of strontites and that of lime next in order: but the 

 amalgam from magnesia, as might be expected from the 

 weak affinity of the earth for water, very slowly changed; 

 when a little sulphuric acid was added to the water : how- 

 ever, the evolution of hvdrogen, and the production and so- 

 lution of magnesia were exceedingly rapid, and the mercury 

 soon remained free. 



I was inclined to believe that one reason why magnesia 

 was less easy to metallize than the other alkaline earths, was 

 its insolubility in water, which would prevent it from being 

 presented in the nascent state, detached from its solution at 

 the negative surface. On this idea I tried the experiment, 

 using moistened sulphate of magnesia, instead of the pure 

 earth ; and I found that the amalgam was much sooner ob- 

 tained. Here the magnesia was attracted from th? sulphuric 

 acid, and probably deoxygenated and combined with the 

 quicksilver at the same instant. 



The amalgams of the other bases of the alkaline earths, 

 could, I found, be obtained in the same manner from their 

 saline compounds. 



I tried in this way very successfully, muriate and sulphate 

 of lime, the muriate of strontites, and of barytes, and ni- 

 trate of barytes. The earths separated at the deoxygenating 

 surface, there seemed instantly to undergo decomposition, 

 and seized upon by the mercury, were in some measure de- 

 fended from the action of air, and from the contact of water, 

 and preserved by their strong attraction for this metal. 



III. Attempts to procure the Metals of the alkaline Earths ; 

 and on their Properties. 

 To procure quantities of amalgams sufficient for distilla- 

 tion, I combined the methods I had before employed, with 

 those of M. M. Berzelius and Pontin. 



The earths were slightly moktened, and mixed with one* 

 N 4 third 



