268 



Researches on the Commercial Potash 



ted. I am the more particular in adverting to this fact, because I 

 have heard it urged as an objection to some samples of potash that, 

 by exposure to the air, they rapidly deliquiated or became moist. 

 But of course the more rapidly potash undergoes this change, the 

 more pure is it to be considered. It should not however be under- 

 stood, that moist potash is the purest ; for in this state, it contains a 

 large quantity of water, which adds nothing to its value. I per- 

 formed an experiment to ascertain the increase of weight which com- 

 mon potash experiences, by exposure to a moist atmosphere. The 

 mass weighed four hundred and thirteen grains. After three hours 

 exposure, it had gained five grains ; in twenty four hours, its weight 

 was increased twenty seven grains, or more than six per cent. 



As I have observed, the presence of soda was inferred in several 

 of the specimens and, had time permitted, might probably have been 

 detected in all. In two of these, however, it existed in such large 

 proportion, that it could be readily separated by adding muriatic acid, 

 and carefully crystallizing the solution. I would particularize No. 7 

 in the following table, which was designated by the inspector, as 

 " highly salted," a decision which my analysis fully confirmed. It 

 is probable, for reasons which have been given in the former part of 

 this communication, that the soda existed in the form of carbonate, 

 and its occurrence, in such large quantity, may be fairly ascribed to 

 the employment of common salt. 



The following table will exhibit the comparative purity of the spe- 

 cimens which I analyzed, and in order to show in what respects they 

 differ from the American potash, analyzed many years since by the 

 celebrated Vauquelin, I have prefixed his results, reduced to the 

 same number of grains which I employed. 



Table showing the composition of several varieties of Commer- 

 mercial Potash. 



