532 



II. " On Chemical Affinity, and the Solubility of the Sulphate 

 of Baryta in Acid Liquors." By P. GRACE CALVERT, Esq. 

 Communicated by WILLIAM ALLEN MILLER, M.D., F.R.S. 

 Received October 27, 3855. 



Solubility of the Sulphate of Baryta. 



The author observes that sulphate of baryta is not an insoluble 

 salt, as is generally admitted, for he has found that 1000 grs. of nitric 

 acid, of spec. grav. 1*167, are capable of dissolving 2 grs. of sulphate 

 of baryta ; and what renders the knowledge of this fact still more 

 useful in analytical chemistry is, that the insolubility of this salt is 

 affected even by the weakest nitric or hydrochloric acids ; for whilst 

 0*062 gr. of sulphate of baryta only requires 1000 grs. of nitric acid, 

 of spec. grav. 1-032, to hold it in solution, the same quantity of salt 

 requires 50*000 grs. of pure distilled water to dissolve it. 



What is not less useful to know is, that the solubility of sulphate 

 of baryta is affected in a higher degree by the bulk of the acid than 

 by its strength. The two following tables, taken from amongst 

 many others contained in the paper, will not only illustrate this fact, 

 but will also give an insight into the way in which the experiments 

 were conducted. The first table illustrates the influence which in- 

 creasing bulks of the same nitric acid exert on the formation of sul- 

 phate of baryta, and the second table the action which increasing 

 strengths of acid have : 



TABLE XVI. 



