36 ANALYSIS OF THE PYROPHYSALITi:. 



Alumine 53*25 



Silex 32*88 



Lime 0*88 



Oxide of iron 0*88 



87*89 



Loss by calcination '•••'* 0*75 



Loss in the analysis 11 *36 



100 



Loss appeared The last mentioned loss, which we experienced in several 



not to proceed trials, led us to suspect the presence of an alkali. In con- 



from an alkali. . 



sequence we heated the stone with nitrate of barj'tes, dis- 

 solved in sulphuric acid the mass obtained by this operation, 

 and poured ammonia into the solution. The saline liquor 

 being evaporated, and the salt heated red hot in a platina 

 crucible, we imagined in what remained we discovered traces 

 of a salt with an alkaline base, mixed with sulphate of lime„ 

 but the quantity of which was too small to ascertain its 

 weight. It is even probable, that this salt may have been 

 produced by the reagents. Thus it remained for us to exa- 

 mine, whether this stone did not contain an acid j as the 

 fluoric for instance. 



Examined for T n orc | er to determine this, we saturated with muriatic 

 an a,Ciu. . 



acid the liquor that remained after the precipitation of the 



earthy substances in the preceding experiments, and then 

 added muriate of lime. No precipitate however was ob- 

 tained. We then determined to boil for an hour a portion 

 of the stone, previously reduced to powder, in sulphuric 

 acid. Employing a glass retort in this operation, we placed 

 a vessel filled with lime-water, to receive the gasses, that 

 should pass over during the solution. None however came 

 over, except what was contained in the vessels, and the lime- 

 It contains the water underwent no alteration. We saw however that, the 

 upper part of the retort and part of the receiver had been 

 corroded by fluoric acid. This acid therefore actually exists 

 in the stone, though perhaps in small quantity* or strongly 

 united with its base. Mr. J. G. Gahn observed a more con- 

 siderable extrication of it, by treating with sulphuric acid 

 tUe powder of this stone previously fused with an alkali. In 



our 



