"Pliny recorded processes involving metals, salts, , glass, mortar, soot, ash, and a large variety of s, earths, and s…"

"The Earths are white, inodorous, tasteless, and uninflammable substances—non-conductors of electricity, insoluble in …"

"Earth is one of the four simple substances called elements, or primitive principles; because they are indeed the most…"

"These general considerations are sufficient to convince us, that in nature a substance exists whose properties are di…"

"Earth is not found so pure as the other elements, fire, air, and water, which, though not entirely free from mixture,…"

"But we cannot say the same of earth; for a considerable number of substances are called earths, because they possess …"

"The most general and most probable opinion is, that as only one kind of fire, of air, and of water, so only one kind …"

"Some of the best philosophical chemists have rather chose to admit different kinds of elementary earths, than to inve…"

"Mr. Pott, examining the principal natural earths, divides them into four kinds, the vitrifiable, the , the argillaceo…"

"By 3000 BCE the Sumerians, perhaps while heating copper to make it more malleable, had discovered that more copper co…"