|
COMMENTARY
|
||
|
|
||
|
1. The metals obtained by mining, such as silver, gold, and so on, come from water.
In general, the ideas of Theophrastus on the origin and nature of mineral substances are based on those of his predecessors and teachers, Plato and Aristotle. His brief statement about the formation of metals from water appears to be taken directly from Plato,1 who believed that there were two primary types of substances having the nature of water: one of these was the liquid kind of water, which included any material that normally existed as a flowing liquid; and the other was the fusible kind of water, which included substances, such as metals, that could be made to flow by the action of heat. Plato describes the nature and formation of gold as follows: "Of all the substances which we have ranked as fusible kinds of water, that which is densest is formed of the finest and most uniform particles. This is a unique kind, tinged with a glittering and yellow color, that most precious of possessions known as gold, which has filtered through rocks and there congealed . . . ."2
The ideas of Aristotle on the origin of metals are somewhat more complex. According to him,3 the metals originated from the imprisonment,of vaporous exhalations in the earth, particularly in stones, where they were congealed by some sort of drying process, and as a result a metallic substance was generated^Since it was supposed that this process was similar to the freezing of water, the metals were considered by analogy to be water, but only in a certain sense. Aristotle believed that metals consisted of matter which might have become water but could no longer do so. He did not consider them as originating from qualitative changes in actual water. On the whole, so far as we can judge from his meager statements here, the ideas of Theophrastus on the origin of metals were in somewhat closer agreement with the ideas of Plato than with those of his immediate predecessor.
The statements of Theophrastus in this first section of the treatise also indicate that he was more inclined to follow the theories
1 Timaeus, 58D. 2 Timaeus, 59B. 3 Meteorologica, III, 6.
•63·
|
||
|
|
||