A SYSTEM OF 
SECT. EXXVL 
ObSE RVA TION on the Gar n e i’ Kind. 
When this kind contains fo much of iron as 
renders it profitable to be worked^ it is confidered 
as a good iron ore^ and no notice is taken of its 
natoral character, in the fame manner as is done 
with clays and jafpers that contain iron ; for the 
riciinefs of metal in thefe rifes in a gradual pro- 
greflion, until they accjuire the colour and ap- 
pearance of the iron itfelf. 
Thus a kind of garnet is melted in a furnaccj 
not far from Eibenftockj in Saxony, and the 
fame fpecies is found, and might alfo be em- 
ployed at Moren, in Weftrnanland. Jafpers are 
for this purpofe melted in Hungary, and clays in 
England ^ but as the greated part of the garnet 
kind contains fo littk iron as to yield only be- 
tween fix and twelve per cent, which is too poor 
to be worked any where in the world as a profita- 
ble iron ore, the reft and the greateft part of it 
being a mere earth, it muft in a natural hiftory be 
confidered and ranked among the earths. 
The tin grains fnould have got a place in this or- 
der, I. If I had known any of them to contain tin in 
fo fmaii a portion as five per cent, as this quan- 
tity of tin is the moft that ever can be obtained 
from the garnets ; 2. If it was proved that a calx 
of iron always was mixed with it, as in the 
garnet I and, 3. If I did not believe that the 
The fsiineral name of Call^ has been ufed by fome autlif'rs r.s fy.- 
yionymous wilh cockles, and is even confounded together ac the mines; but 
die Call, definitely fpeaking, is the fubaaiicc called WolSVam by the Ger- 
jiians. ^c. 
Garsetis though fmall, are often found in micaceous flones in England ; 
|){st<exti'eme good garnets are found in great plenty alfo in like flonei. in Scot- 
iand. D. C. ' 
tin 
