8 account: of a MINERAL 



the other. The difference marks the quantity of water which 

 enters into the compofition of the ("par. By heat 38.79 />^r cf«?. 

 is expelled, while there is a lofs by folution of 30.20. 



Hence 100 parts contain of earthy bafis, 61.21 



carbonic acid, - 30.20 



water, - 8.59 



100 



16. As I hope to be able to render it probable, that this 

 earthy bafis differs from any of the hitherto known fpecies of 

 earth, I fhall, to fave circumlocution hereafter, take the liberty 

 of calling it by the name of Strontites ; by which I wilh to be 

 underftood to mean the earthy matter in a ftate of purity, in 

 the fame way as lime and barytes denote the pvire earthy bafes 

 of calcareous fpar and of aerated barytes. 



17. Of the qualities of the Strontites it will be proper to add 

 fome more particulars. 



Strontites has a pungent acrid tafte. When brayed in a 

 mortar, the fubtle powder that arlfes is penetrating and offen- 

 five to the noftrils and lungs. It is foluble in water in the pro- 

 portion nearly of 2.7 grains to the ounce, at temperature 60. 

 The folution is clear and tranfparent, pofTeffing a flrong tafte, 

 not unlike that of lime water ; it changes to a green, papers 

 flained with the juice of violets or radilhes. On expofure to 

 the air, ftrontitic water quickly acquires a cruft on the furface, 

 in confequence of the earth attrading carbonic acid and beco^ 

 ming infolublc. 



18. Hot water diffblves a much larger quantity than cold, 

 and depofits the Strontites as it cools in the form of colourlefs 

 and tranfparent cryftals. The moft ready way of obtaining 

 thefe is to pour a quantity of boiling water into a Florence flafk, 

 and then to throw in the recently calcined fpar in fmall pieces. 

 After the ebullition that enfues hasceafed, fliake the fla{k well, 



I and. 



