STRONTITES. 
137 
or a mixture of it with calcareous earth ; until lately that Dr. Hope 
of Glaſgow employed himself in examining it, by a number of expe 
riments, which he communicated to our Royal Society here. His 
experiments were very judiciously planned, and the conclusions he 
drew from them are perfectly well supported. I ſhall now give a ge 
neral abstract of them. 
He finds reason to conclude that it is a peculiar species of alkaline 
earth, different from any described before. The mine in which it is 
found intermixed with other spars is in the west of Scotland, near a 
village called Strontian : He therefore gives it the name of STRONTITES. 
1. The carbonat of strontites of Dr. Hope is of a specific gravity 
from 3.650 to 3.726. The natural carbonat of barytes is 4.338. 
The carbonat of lime is about 2.700. 
2. Its external characters are, —considerable hardnèss, fibrous or 
crystallized texture, muddy transparency, and colour inclining to 
yellow or green. 
3. It is insipid, but has a little solubility in water. Four ounces of 
distilled water being boiled with 10 grains of it in fine powder, dif 
solved 21—758. 
4. The gas extricated during its effervescence with acids is car 
bonic acid gas ; and it loses 30.2 per 100 during effervescence. 
5. The greatest heat of a common open fire is not sufficient to 
expel its air, but only makes it decrepitate a little, and become opaque 
by the loſs of some water. 
A violent heat in a fmith's forge, of 45 minutes, applied to a fmal 
maſs of strontites inclosed in a Sturbridge clay crucible, and which 
softened the crucible, melted the outside of the mass into a green glass; 
while, within this vitrified crust, the rest was white, opaque, and 
caustic. When it is thus rendered caustic, it loses 38.79 per 100 
of its weight. With water it now unites in the fame manner as 
quicklime, but more violently, and is flaked by the air in the fame 
manner. The vitrified part being dropped into muriatic acid, is slowly 
VoL. II.