Annibale Mottana
Abstract
Theophrastus' thought about metals according to his surviving fragments and to Greek, Latin, Syriac and Arabic testimonies. An inspection of Theophrastus' writings, namely his book «On stones» (De lapidibus ), his three major books and eleven of his fragments, all of which came down to us either directly in Greek or through Syriac and Arabic translations, shows as many as 42 statements which concern metals. Moreover, a survey of the works of Greek, Latin, Syriac and Arabic authors adds another 24 quotations concerning metals taken from Theophrastus' teaching as well as 34 references inspired by him, but reported anonymously. All statements are short, and most of them are even cryptic. Nevertheless, on the basis of such a meagre, random evidence, an attempt is made at reconstructing Theophrastus' treatise «On metals» (De metallis ), which was already lost in antiquity despite having been mentioned by Diogenes Laertius and later Greek authors down to the 11th century AD. Such a treatise is shown to have been written in between 323 and 315 BC for teaching purposes, and to have included inquiries performed in the years 340-335 BC according to Aristotle's method of investigating natural facts, but still under the influence of Plato's theoretical opinions by which Theophrastus had been imbued when attending his school (354-347 BC). The treatise consisted of at least two sections: a mining one concerning winning and dressing of metalbearing ores, and another, metallurgical one concerning their refinement and the treatment of the extracted metals, as well as, possibly, giving some examples of their applications. It is pointed out that Theophrastus never adhered strictly to Aristotle's theory that metals are the result of underground condensation of the wet exhalation reacting with earth, but maintained a belief in Plato's thought that metals are solid forms of the watery element. Indeed, Theophrastus always emphasised their property of melting i.e., turning to liquid, when submitted to fire, with subsequent changes in their properties, such as shading in their color due to alloying i.e., entering solution with other metals. This agrees with his style of endeavouring explanation of natural phenomena by the direct way of simple observations.
