BISULPHATE OF SODA AS A SUBSTITUTE FOR 

 THE BISULPHATE OF POTASH 



IN THE DECOMPOSITION OF MINEEALS, ESPECIALLY 

 THE ALUMINOUS MINEEALS. 



In referring to the more recent works on analytical chemistry 

 I perceive that the bisulphate of potash is still used to the almost 

 utter exclusion of bisulphate of soda in rendering certain min- 

 erals soluble : and it is still recommended as the proper agent 

 to fuse with aluminous minerals, as corundum, emery, etc. 



This subject occupied my attention to a considerable extent 

 when engaged in the preparation of two memoirs on the geology 

 and mineralogy of emery, presented to the French Academy 

 of Science in 1850, as well as in some investigations I am now 

 making on the emery from Chester, Mass. In the above re- 

 searches I had a large number of corundums and emeries to 

 analyze. The powdered minerals were fused with the bisul- 

 phate of potash in the usual way, and I found no difficulty 

 in decomposing the minerals; but unfortunately during the 

 operation a double salt of potash and alumina is formed which 

 is almost insoluble in water or in the acids, and it is only by a 

 solution of potash that it is first decomposed and afterward 

 redissolved. There are many disadvantages and delays at- 

 tendant upon this method which experience soon exhibits, as 

 the constant deposition of alum if the solution is not kept quite 

 dilute. I therefore experimented with the bisulphate of soda, 

 knowing that the double salt of alumina and soda was quite 

 soluble, and my results were everything that could be desired; 

 for while the soda-salt gives a decomposition at least as com- 

 plete as the potash-salt, the melted mass is very soluble in 

 water, and in the future operations of the analyses there is no 

 embarrassment from a deposit of alum. The manner of em- 

 ploying the bisulphate of soda in the analysis of emery is 

 referred to in the article on the emery of Chester, Mass. 



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