AUP PEN DE Ox. 141 
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POSTSCRIPT TO THE HISTORY. 
ON Monday, the 4th of November 1793, Dr Hore, Pro- 
feffor of Medicine in the Univerfity of Glafgow, read a paper, 
entitled, 4n Account of a Mineral from Strontian, and of a peculiar 
Species of Earth which it contains. Want of room, and the length 
_of the differtation, prevent its appearance in the prefent volume. 
But as the difcovery of a new earth cannot fail to be interefting, 
it has been thought proper to trefpafs a little on the order of 
time, and to infert here the following abftraa. 
THE mineral is found in the lead-mine of Strontian in Argyle- 
fhire. It was brought to Edinburgh about fix years ago in confi- 
derable quantity. It was generally received as the aérated barytes. 
At that time, Dr Hope had fome doubts of its being the barytic 
{par, and ufed, in his prelections, when he filled the chemical chair 
in the Univerfity of Glafgow, to mention fuch of its diftin- 
guifhing characters as he had then difcovered. The Strontian 
{par fometimes is colourlefs, oftener it has a greenifh or yel- 
lowifh hue. Its texture is fibrous, and it frequently fhoots in- 
to cryftals, which are flender fpiculz or hexagonal columns. 
The fpecific gravity of it goes from 3.650 to 3.726. 
Tuts mineral is infipid, and requires nearly 800 times -its 
weight of water to diffolve it. It effervefces with acids, and 
during folution carbonic acid is difengaged to the amount of 
30-2 grains per cent. When moderately heated, it crackles, 
and lofes its tranfparency. By a very vehement heat, the car- 
bonic acid is expelled, and the mafs lofes 38.79 per cent. of its 
weight, and ceafes to effervefce with acids. - The calcined {par, 
when water is poured on it, fwells. burfts, and becomes hot in 
a greater degree, and with more rapidity, than lime. It is 
acrid, 
