*44 BISTORT of the SOCIETT. 



acrid, and is foluble in water. The folution of it has a tafle 

 not unlike that of lime-water, changes to a green, paper ftain- 

 ed with the juice of violets or radifhes, and on expofure to the 



air quickly acquires a cruft on its furface. The earth of 



Strontian mineral, which Dr Hope denominates Strontites, re- 

 quires about 1 80 times its weight of water, at a low tempera- 

 ture, for its folution. In boiling water, it diffblves much more 

 abundantly, and is depolited during cooling in the form of 

 cryftals. Thefe cryftals are tranfparent and without colour, in 

 the mape of quadrangular plates, fometimes fquare, more com- 

 monly oblong, with the margins cut like a wedge. Now and 

 then are feen folid parallelopepids and cubes. On expofure to 

 the action of the air, they become white, powdery and effer- 

 vefcent, lofing almoft T V of their weight. In a dull red 

 heat, they undergo the aqueous fuiion, and a white refractory 

 powder remains. They contain 68 per cetit. of humidity. Di- 

 ftilled water, at temperature 60, diffolves them flowly, in the 

 proportion of 8.5 grains to the ounce. An ounce of water, at 

 a temperature fuificient to keep the folution boiling, diftblved 

 no lefs than 218 grains. This remarkable folubility affords a 

 difcriminating feature of this earth. An hundred parts of the 

 Strontian mineral confift, of earthy bafis 61.21, of carbonic 

 acid 30.20, and of water 8.59. 



Dr Hope next details at great length the phenomena attend- 

 ing the action of fulphuric, nitric, muriatic, acetous, oxalic, 

 tartaric, fluoric, phofphoric, arfenic, fuccinic, boracic and car- 

 bonic acids on Strontian mineral in mafs and in fine powder, 

 and defcribes the properties of the refulting compounds in re- 

 gard to fenfible qualities, effects of air and of heat, and folubi- 

 lity in water. It may fufEce to extract only from what is faid 

 on the action of nitric and muriatic acids. Strong nitric acid 

 fcarcely attacks the fpar, unlefs affifled by heat. If duly di- 

 luted, it diffolves it rapidly and completely. The folution is 

 colourlefs and tranfparent, and having a pungent tafte, yields 

 3 cryftals 



