Csmhiftaiions of Strnnt'iitn with SUtx and Alumtne. %!^ 



the producSt was a grey fonorous mafs, cracked in various places, thg parts of vfrhich adhered 

 together with confiderable force. In this ftate, it had no very evident tafte, but when pulve- 

 rized it was flightly cauftic ; when put into water, whether in the lump or in powder, this 

 compound neither produced heat nor fwelled up, as is the cafe with the pure ftrontian. It only 

 became fomewhat whiter. 



Experiment 2. The fubftance lafl: fpoken of was pulverized and boiled in water, vvhich 

 dilTolved it much lefs abundantly than pure ftrontian, but the water acquired a flight alkaline 

 tafte, and foon became covered with a white pellicle : it did not afFord cryftals. When fatu- 

 rated with nitric acid, this folution afforded, by evaporation, a jelly in confiderable abundance. 



Experiment 3. Another portion of the fame matter pulverized and moiftened with a 

 little water, was totally diflblved, by the muriatic acid, and the folution afforded by evapora- 

 tion a very abundant jelly, which, after wafliing and drying, prefented all the charaiters of 

 filex. The nitric and acetous acids produced the fame efFe6t on this fubftance. 



Experiment 4. Five parts of pure ftrontian in fine powder, and one part of alumine, re- 

 cently prepared, and ftill humid, were heated together with water, and when the liquor had 

 fully boiled, it was filtered, and contained much undifTolved matter. The filtered liquor had a 

 flight alkaline tafte, but did not cryftalize, though a much greater quantity of the earth had 

 been ufed, than could be diflblved without heat. 



This folution was then faturated with muriatic acid, and being afterwards mixed with 

 ammoniac, afforded a fmall quantity of flocculent matter, which was alumine. 



Strontian confequently poflTefles the property of favouring the folution of alumine in water ; 

 but what is more remarkable is, that the alumine, on the other hand, rendered a great quantity 

 of the ftrontian infoluble ; for the water did not, in this cafe, diflblve one-tenth part of what 

 it would elfe have taken up. 



The examination of what remained on the filter, proved that the ftrontian became infoluble, 

 by an intimate combination between thefe two earths; and it is probable, that if a greater 

 quantity of alumine had been prcfcnt, there would not have been a particle of mere ftrontian 

 diflxjlved. 



The refidue was, in faft, foluble in acids, with fcarcely any effervefcence; its folution af- 

 forded a flocculent precipitate of alumine, by means of ammoniac 5 and the fupernatant liquor 

 formed a very abundant depofition, when carbonate of potafli was added. 



It will not, therefore, be furprifing, if a combination of thefe two earths fliould, hereafter, 

 be found in nature. 



Concerning BaryteS', 

 Experiment liOne hundred and fifty parts of cauftic baryles were mixed, as accurately as pof- 

 fible, with fifty parts of filex, and the whole was afterwards ftrongly heated for an hour and a 

 half in a crucible of platina. The mafs was in one fingle piece, cracked in various places, but 

 without the cohefion obferved in the experiment with ftrontian. Its colour was a light apple 

 green, its tafte almoft mild, and it did not heat with water, whether it was immerfed in lumps, 

 01 in powder. It prcferved its green colour in the water. 



Ra Experiment 



