The light duſky blew concretes as well as the green, called by ſome Copper okers, yield a great deal of very good Copper when they are pure, which may be known from their colour and weight ; but thoſe that are more light are mixed with unmetallick earth, and thoſe that are yellow, containing iron oker ; on which account they are the more difficult to be met with, and yield leſs Copper of an inferior ſort.
Source: wiktionary
The acid, now impregnated with a new matter, paſſes on ; till meeting with ſome other convenient nidus, it lodges in that, and thereby acquires a freſh impregnation, perhaps at laſt totally unmetallick ; or, for want of meeting with a proper nidus, appears at the ſurface, weakly or ſtrongly tinctured with thoſe principles it had laſt imbibed.
Source: wiktionary
The robot bowed. “Thank you, gentlemen,” it said, in sweet, unmetallic accents. “Now if you will please escort me to the meeting place …”
Source: wiktionary