MINERALOGY. 
125 
tis et jovis mhta : Spima Lupi^ or JVoU 
fram 
I. With coarfe fibres. 
a. Oi an iron colour, from Altenberg 
in Saxony, This gives to the glafs 
compofitions, and alfo to borax and 
the microcofmic fait, an opaque whitifh 
yellow colour, which at laft vanifhes. 
SECT, CXVIIL 
Obseiivations on the Manganese. 
Though it may feem difficult to many, to diftiii- 
guifh the kinds of manganefe by their appearance, 
or external marks ; yet it is extremely eafy to 
know them by experiments made in the fire, if 
attention is had to the above-mentioned pheno- 
mena (Se(S:. cxiii.). From hence it is not difficult 
to comprehend why manganefe has hitherto been 
either omitted, or erroneoufly ranked in fyftems, 
viz. becaufe it has, like many other mineral 
bodies, been examined only by fight, while the 
more troublefome method of examining it in the 
fire, has been overlooked. 
Some might perhaps imagine the manganefe' 
to be the remainder of fome metal, which cannot 
be reduced again into its metallic ftate ; but it 
ought to be remembered, that no metal can, by 
any means yet known, be brought to an abfoiutely 
irreducible earth or calx, unlefs perhaps by the 
burning-glafs, and therefore there is no reafon to 
fufped that nature gives fuch a produftion. Ig- 
* Wolfram is a name which is alfo fometimes given to 
mock lead, and foinetimesno cockle, or fhirl, as alfo to other 
minerals ; however, it is chiefly given to this fpecies of man- 
ganefe, when it occurs in the tin-mines. E. and D. C, 
norance 
