Page:Theophrastus - History of Stones - Hill (1774).djvu/197

 its Softnes; but when it is afterwards burnt and wetted with Oil, it becomes black and olid. Veels of different Kinds, for the Service of the Table, are made of this.

LXXV. All Subtances of this Kind are to be worked on by Iron Intruments; but others there are, which, as before oberved, will not be touched by them, but mut be cut by other Stones; and others yet, which may be cut with Iron, but the Intruments mut be dull and blunt : Which is much as if they were not cut by Iron.