MINERALOGY 
95 - 
SEC T. LXXXVII. 
Indurated Bole, Bolus indurata. 
A. Of no vifible particles, Particulis imfaU 
pabilibus. 
This occurs very often in form of flate^ 
or -layers in the earth, and then is made 
ufe of as an iron ore. However, it has 
ufually been conudered more in regard to 
its texture, than to its conllituent parts, 
and has been called date, in common with 
feveral other earths, which are found to 
have the fame texture. 
a. Reddifh brown, from England f. 
b. Grey, from Coalbrookdale, in Shrop- 
fhire, and mod: collieries of England.' 
SECT. LXXXVIIL 
B, Of fcaly particles, Particulis fquamjls t 
The hornblende of the Swedes. 
holes is ftill thought to comprehend fo many varieties. Thus 
the Cologne clay (Sedl. Ixxviii.) is by the druggifls ranked 
’among the white healed earths, and is called a ^Mhite hole : 
and this, fame clay is by the Swediih potters called 'Englesk 
jord, or Engliih earth ; and by the tobacco-pipe makers, 
Pip-lera, or pipe clay, &c. which fhews how great a confulion 
there mull enfue, if the knowledge of thefe bodies w.as not 
founded upon a furer ground than the colour, figure* and 
names invented by common mechanics. Since the moft part 
of thefe terra jigillata^ or fealed earths, are found to contain 
iron, I conclude, that the bole muft be a martial clay ; and, 
as fuch, it feems to be more fit for medical uies than other 
clays, if any dead earth mull beufed internally, when there i$ 
fuch an abundance of finer fubftances. 
t Jn moft collieries between the Teams of coal, as at Han” 
nam, in Kingfwood, near Jorifloi, Bianavon, in Monmoiith" 
ihire, &c. D* C. 
Is 
