Of Magnefian Earth. 
453 
Sir. T. Bergman relates,* that he procured a 
fait, fimilar to the fal catharticus amarus, by 
lixiviating the earthy matters, feparated by wafli- 
ing from the filver ore of Sahlberg, on the 
furface of which the fait forms, by expofure to 
the air. One hundred weight of the earth 
yielded fixty-five pounds of this fait. M. Mon- 
net, alfo, difcovered a kind of Schiftus, which 
on calcination, and lixiviation, furniftied a fmall 
portion of the fame fait. 
Magnefian earth may alfo be feparated, by 
means of vitriolic acid, from fome fpars, mar¬ 
bles, and other earthy and ftony bodies of which 
it forms a component part. 
The compound fpar, defcribed by Mr. 
Woulfe, f contains, in 100 parts, 60 of mil'd 
calcareous, 35 of mild Magnefia, and 5 of iron. 
One hundred parts of Creutzenwald (lone 
contain 12 of mild Magnefia. 
The Kolmord marble , the Pietra Ealchinay the 
Verde Antico , and the Griotte, a red marble from 
Autun , all contain fmall portions of Magnefia. 
The Spuma Maris , an earthy fubftance, from 
which the Turkey tobacco-pipes are made, is 
faid to confift of equal parts of magnefian, and 
filiceous, earths. 
# Bergman de Magnefia. 
| Phil. Tranf. vol. LXIX. p. 29, 
Steatite, 
