"In Alexandria two streams of knowledge met and fused together... The ancient Egyptian industrial arts of metallurgy, dyeing and glass-making... and... the philosophical speculations of ancient Greece, now tinged with ancient mysticism, and partly transformed into that curious fruit of the tree of knowledge which we call Gnosticism. ...the result was the "divine" or "sacred" art (...also means sulphur) of making gold of silver. ...during the first four centuries a considerable body of knowledge came into existence. The treatises written in Greek... in Alexandria, are the earliest known books on chemistry. ...The treatises also contain much of an allegorical nature... sometimes described as "obscure mysticism." ...the Neoplatonism which was especially studied in Alexandria... is not so negligible as has sometimes been supposed. ...The study of astrology was connected with that of chemistry in the form of an association of the metals with the planets on a supposed basis of "sympathy". This goes back to early Chaldean sources but was developed by the Neoplatonists."