II. On chemical affinity, and the solubility of the sulphate of baryta in acid liquors

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 increasing bulks of the same nitric acid exert on the formation of sulphate of baryta, and the second table the action which increasing strengths of acid have: