( 48* ) 
yet (the Woods having been apply 'd to more advanta- 
ges Ufes) they are there entirely negleded. 
When it is moft pure, 1 find the Oar under three 
different Appearances. 
Paper the firfl contains a Piece of rich dry Iron Oar, 
whofe Scrapings exadly refemble an ALkohol Martis : 
This Kind of Iron Oar has very nearly the Colour of 
common Clay. 
Paper the fecond contains a Piece of rich Iron Oar, 
with Part of the Wall of the Load formed by a 
Concretion of yellow Cryftals. In this Stone the Iron 
radiates from Points forming Segments of Spheres, and 
where thefe Spheres leave any Interfaces, you will find 
a Crocus, or Oker. 
Paper the third contains a Stone of Iron of the Kind 
ufed for burnifhing Plate j it is of the Species of 
the Hematites. 
Both thefe laft Stones fcrape into a deep Crocus. 
From the fecond Inftance we may conjedure, that 
the yellow Colour in Cryftals arifes from a Crocus en- 
tangled with the ftoney Salts. 
Though the Want of Wood in Cornwal deprives it 
of the Advantages it might otherways reap from Iron 
as a Metal, we (hall neverthelefs find it far from being 
a ufelefs Oar, when we conlider it as fometimes im- 
pregnating the Waters with vitriolick Salts, thereby 
making them a proper Menftruum for dilTolving the 
diffeminated Particles of Metals- fometimes deftroying 
the fulphureous Menflrua, which (tho* they diifolve 
the diileminated Metals) do neverthelefs obflrud their 
new Concretions and fometimes as being it felf the 
Magnet by which the metallick Particles are attraded 
into new Concretions. 
Of 
Ttt 
