TA4 HISTORY of the SOCIETY. : 
acrid, and-is foluble in water. The folution of it has a tafte 
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 180 times its weight of water, at a low tempera- 
ture, for its folution. In boiling water, it diflolves much more 
abundantly, and is depofited during cooling in the form of 
eryftals. Thefe cryftals are tranfparent and without colour, in 
the fhape 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 + of their weight. In a dull red 
heat, they undergo the aqueous fufion, and a white refractory 
powder remains. They contain 68 per cent. of humidity. Di~ 
{tilled water, at temperature 60, diflolves them flowly, in the 
proportion of 8.5 grains to the ounce. An ounce of water, at 
a temperature fufficient to keep the folution boiling, diflolved 
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 fuffice to extract only from what is faid 
on the aétion of nitric and muriatic acids. Strong nitric acid 
fcarcely attacks the fpar, unlefs affifted 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 
