Dr Turner's Analysis of' Oxahverite. 119 



fine powder to the action of muriatic acid, it suffers complete 

 decomposition. A gelatinous residue remains, which, after 

 exposure to a red heat, is found to be a hght white powder 

 readily soluble in a concentrated hot solution of the carbonate 

 of soda, and possessed of all the properties of pure silica. The 

 acid solution had a yellow colour indicative of the presence of 

 the peroxide of iron. The addition of muriate of baryta did not 

 disturb the transparency of the liquid. Pure ammonia caused 

 a reddish-brown flocculent precipitate, consisting of the peroxide 

 of iron and alumina. On adding oxalate of ammonia to the 

 filtered solution, a copious white precipitate of the oxalate of 

 lime ensued. The residual liquid, evaporated to dryness and 

 ignited, gave a white fusible residue, in which carbonate of am- 

 monia and phosphoric acid could discover no trace of magne- 

 sia, but which, with the muriate of platinum, yielded a copious 

 precipitate of the yellow muriate of platinum and potash. The 

 saline residue did not possess the property of communicating 

 a yellow tint to flame, from which circumstance the total ab- 

 sence of soda is inferred. 



From the preceding characters, it follows that the oxahve- 

 rite is composed of silica, lime, potash, oxide of iron, alumi- 

 na, and water. In addition to these ingredients I have like- 

 wise discovered a trace of fluoric acid. In the preliminary 

 examination I had indeed failed in detecting this substance ; 

 but when, on observing the similarity in the composition of 

 oxahverite and apophyllite, I repeated the experiments with 

 a larger quantity of the mineral, I succeeded in procuring une- 

 quivocal indications of its presence. From a deficient supply 

 of the oxahverite I have been unable to determine the precise 

 proportion of fluoric acid ; but the quantity is very minute, 

 and I apprehend falls far short of one per cent. 



With respect to the degree of oxidation of the iron, it is 

 certain that this metal is in part at least in the state of perox- 

 ide ; for, on acting upon the mineral with muriatic acid in a 

 close vessel, and pouring the liquid into a boiling solution of 

 the ferro-cyanate of potash, a blue precipitate appeared. 



To discover the proportion of the constituents of this mineral, 

 I exposed 22.95 grains of the fresh crystals, in fine powder, to 

 the action of strong muriatic acid for forty-eight hours. The 



