146 HISTORY of th SOCIETY. 
Ac the folutions of Strontites in acids are decompofed by 
the three alkalies in their effervefcent ftate, and in part by vir+_ 
tue of a double elective attraction. The artificial carbonate of 
Strontites thus obtained, parts with its fixed air more readily 
than the native. Pure potafs feparates Strontites from nitric 
and muriatic acids, but partially, and in a cryftalline form. 
Neither pruffiate of potafs nor of lime caufea precipitate in any 
of the folutions. 
SrRoONTITES generates a hepar with fulphur either in the hu- 
mid or dry way. Its cryftals are fparingly diffolved by alco- 
hol; a yellow coloured tincture refults. 
Arter fini‘hing the detail of the properties of the Strontian 
mineral and its earthy bafis, Dr Hope proceeds to enquire, whe- 
ther this foflil and its earth are fimilar to any that are already 
known. He concludes they are not. Strontian fpar refembles 
moft the aerated terra ponderofa, and in feveral refpe&ts has a 
ftrong analogy with it; yet it effentially differs. 
Irs fpecific gravity is lefs, it parts with its carbonic acid 
when urged by heat, fomewhat more readily, and without fuf- 
fering fufion ; when calcined, it imbibes moifture with vaftly 
greater avidity, {welling and cracking with more heat and 
noife. Strontites diffolves much more abundantly in hot wa- 
ter than barytes, and the form of the cryftals of thefe pure 
earths is very diflimilar. The compounds generated by Stron- 
tites differ from thofe of barytes. It will fuffice to mention 
the nitrate and muriate. This earth, united to nitric and mu- 
riatic acid, forms falts that fuffer changes from expofure to air, 
which do not happen to the nitrate and muriate of barytes. 
They are likewife much more foluble in water, and have cry- 
ftals of a peculiar figure. , 
Tue combinations of Strontites with acids are not, like thofe 
of barytes, decompofed by prufliate of lime or of potafs. 
STRONTITEs 
