SeyberPs Analysis of the Maclureite.. 339 



orated to a dry saline mass, and the residue was exposed 

 to a red heat, lo expel the aramoniacal salts ; the fixed salt 

 weighed 0.12 granimes ; when treated with water it dissol- 

 ved, leaving 0.02 grammes of insoiuhle matter, the filtered 

 solution, on being siowiy evaporated, furnished very minute 

 irregular cubes, which, when dried and exposed to the at- 

 mosphere, did not deliquesce ; they were dissolved in wa- 

 ter, and the concentrated solution when trc^ated with the 

 muriate of platina, gave a yellow precipitate of muriate of 

 potash and platina, which was very abundant in proportion 

 to the quantity of salt employed ; the alcali thus proved to 

 be potash, and the 0.10 grammes muriate of potash are 

 equivalent to 0.06326 grammes of potash on three grammes, 

 or 2.108 per 100. 



The products of this analysis are as follows :— 



Ptr 100 Paris. 



92.7?4 

 100.000 



7.226 Loss. 



From the preceding result I was satisfied, that this mine» 

 ral must contain some other constituent than those whicl) 

 1 had detected in it, and on comparing the oxygen of the si- 

 lica with that of the magnesia, it appeared very probable, 

 that it might be an acid. I searched for boric acid without 

 success. To discover Fluoric acid, I proceeded in the 

 following manner, 1st, a portion of the pulverized mineral 

 was heated with an excess of sulphuric acid, and a piece of 

 glass was exposed to the fumes, which were disengaged from 

 the mixture, but it exhibited no signs of corrosion ; from 

 this experiment, I could not conclude the absence of fluor- 

 ic acid, for the silica contained in the mineral would proba- 

 bly have been sufficient to saturate it, and thereby pre- 

 vent its action on the glass. 2. Three grammes of the 

 pulverized mineral were fused, during thirty minutes, in a 



