DETERMINATION OF ALKALIES IN MINERALS. 217 



duce the mixture in a platinum crucible, heat to bright redness 

 in a furnace * from thirty to forty minutes. 



51. There is no silicate which after having undergone this 

 process is not easily dissolved by hydrochloric acid. For the 

 action of the lime to have been complete it is not necessary that 

 the mass should have settled down in a perfect fusion. The con- 

 tents of the crucible are dissolved, and the analysis continued 

 as pointed out in 19, 20, 21, etc. 



52. This method insures the obtaining of every particle 

 of the alkalies in the mineral examined, requiring no more 

 precaution than any good analyst is expected to take in the 

 simplest of his processes, and not the least of the advantages is 

 the ready method of separating all the other ingredients and 

 the small accumulation of water arising from the little washing 

 necessary. ' 



a more speedy method of separating the alkalies directly 

 from the Lime Fusion for both Qualitative and Quanti- 

 tative Determination. 



53. As soon as the fusion with carbonate of lime and sal 

 ammoniac gave evidence of the mineral being so thoroughly 

 attacked, the question naturally arose as to the condition the 

 alkalies were in after the fusion, and the possibility of dis- 

 solving them out by the agency of water alone, at least for 

 the purpose of qualitative determination. Experiments directed 

 to this object soon made it evident that the alkalies might be 

 obtained from any silicate without resorting to the use of acid 

 as a solvent for the fusion. 



54. The mass as it comes from the crucible is placed in a 

 capsule with water, and then heated in a sand-bath or over 

 a lamp for two or three hours, renewing the water from time 

 to time as it evaporates. The mass disintegrates very shortly 

 after being placed in the water. The contents of the capsule 

 are next thrown on a filter, and the water passes through con- 

 taining the chloride of the alkalies, a little chloride of calcium 

 and caustic lime. All else that the mineral may have contained 



* An ordinary portable furnace with a conical sheet-iron cap from two to 

 three feet high answers the purpose perfectly well, all the requisite heat 

 being afforded by it. 



