Experiments en Stront'tan and Barytes. 171 



Thefs cryftals were fpariiigly foluble in water, 4 oz. of whl h, at 65°Fahrenheit, took up barely 

 ene grain ; and of boiling water, each ounce diffolved only between five and fix grains. The 

 watery folution gave a precipitate of fulphate of barytes, on adding fulphuric acid, and of 

 Pruffiated iron, with the folutions of that metal. In a low red heat, the fait was foon changed 

 into a black, rnafs, confifting of carbonate of barytes and charcoal. The cryftals difTolved 

 readily in diluted nitric and muriatic acids, apparently without decompofition, for the folutions 

 precipitated falts of iron. They were decompofed by carbonate and fuiphate of potalh, a 

 double exchange of principles enfuing. 



Part of the precipitate, obfervcd on adding the Pruffiate of potafh to muriated barytes, is 

 doubtlefs often occafioned by the prefence of fulphate of potafh in the Pruffiated alkali ; an 

 adulteration, which it is difficult entirely to avoid ; but that a double eleiStive afSnity is 

 exerted between the two falts, clearly appears on examining the precipitate. After being 

 repeatedly waQied with diftilled water, muriatic acid will be found to diflblve the greater part 

 of it ; and the folution of the precipitate, in this acid, betrays the prefence of Pruffiate of ba- 

 rytes, on applying the proper tefts. It may, therefore, be received as an eftablifhed faft, that 

 an infoluble, or difficultly foluble Pruffiate of barytes is formed, on adding Pruffiate of potafh 

 to the muriated earth, a property in which barytes differs from all other earthy bodies, and 

 refembles the metals : the fimple affinity of potafh for Pruffic acid is fuperior to that of ba- 

 rytes; for cauflic barytes does not precipitate a perfe£lly pure Pruffiate of potafh. Barytes 

 attradls Pruffic acid more powerfull/ than lime, for Pruffiate of lime is decompofed by pure 

 barytes ; the order of thefe affinities, I believe, has not before been afcertained. 

 2. Relation of Strontites to the Pruffic Acid. 



A folution of pul-e cryflallifed ftrontites deprives Pruffiate of iron of its tinging acid ; but 

 the folution of Pruffiated flrontites is much lefs difpofed to cryflallife than the homologous 

 barytic fait. Indeed I have repeatedly evaporated folutions of Pruffiated flrontites very low, 

 without having been able to obtain any cryftals. I therefore expelled from one portion the 

 whole of the water by a gentle heat ; the dry mafs thus obtained dilTolved readily in water at 

 65", an ounce of which took up 120 grains, and even then did not appear to be fatu rated : 

 but having no more of the fait, I was prevented from afcertaining its exa£l folubility. The 

 dry fait does not deliquiate : in its other properties, it refembles Pruffiated barytes. 



A folution of cauflic ftrontites does not precipitate Pruffiated lime, as barytes does ; ftill, 

 however, adecomjofition probably takes place, but is prevented from being apparent by the 

 folubility of the new compound. This may, alfo, be the cafe, when muriated ftrontites is added 

 to Pruffiate of potafh, or of lime. 



Pure barytes, when added to Pruffiated ftrontites, occafions a precipitate, but a much lefs 

 abundant one, than might be expefted ; hence it is probable that the affinities of thefe two 

 earths for Pruffic sci J are nearly equal in ftrength, as Dr. Hope has fhewn they are, with 

 refpeft to carbonic acid. 



Dr. Pefchier acquaints me, that the fulphate of ftrontites abounds in Syria and in Hungary, 



but not the carbonate. 



Concerning 



