CONVERSION OF THE SULPHATES OF THE 

 ALKALIES 



INTO THE CAEBONATES, TARTRATES, &c, IN THE 

 MOIST "WAY. 



Having had occasion more than once to convert small 

 quantities of the sulphates of the alkalies into carbonates, I 

 have for several years employed a process that has been found 

 both certain and convenient; in some recent investigations it 

 has been used, and as it has never been described it may not 

 be unimportant to explain the nature of the process and its 

 results. The agent used to produce the conversion is carbonate 

 of baryta, made by precipitation; where precise results are 

 required the carbonate should be prepared by carbonate of 

 ammonia. The manner of producing the decomposition is as 

 follows : Dissolve the sulphate of potash in water, using about 

 twenty or thirty grammes of water to every gramme of the 

 sulphate, and saturate the solution with carbonic acid by 

 passing a current of carbonic acid into it; or, what is better, 

 dissolve in the beginning the sulphate in water already satu- 

 rated with carbonic acid ; now add to this solution precipitated 

 carbonate of baryta, in the proportion of about one and a half 

 of the carbonate to one part of the sulphate. It is always best 

 in adding the carbonate to rub it up in a mortar with a little 

 water, so as to form a thick cream, for by so doing it mixes 

 well in the solution. 



This operation is performed in a bottle that can be well 

 corked with a cork or gum stopper; now agitate the bottle 

 frequently, or, what is still better, attach it to a piece of ma- 

 chinery that will agitate the bottle. Many laboratories have 

 such, and it is a very useful one in many experiments. In 

 a longer or shorter space of time the decomposition will be 

 completed; pour the solution into a capsule and heat to the 



