In order that pure mercury may be obtained by this method, an additional operation is evidently needed: namely, the heating of the amalgam and the condensation of the pure mercury volatilized by the heat. Thus the process described by Theophrastus produced an amalgam and not pure mercury. Possibly such impure mercury was all that was produced and used at the time of Theophrastus, though it seems more likely that the amalgam was distilled in order to obtain the pure metal. The separation of mercury by distillation was certainly known a little later in ancient times, since both Dioscorides479 and Pliny480 describe its isolation by this method. Since Theophrastus does not mention that the mixture ought to be heated and a simple distillation performed, it is probable that he did not know all the details of the process used in his day.
This passage is not only the first account of the isolation of mercury from cinnabar but also the earliest description of any method of isolating a metal from one of its compounds.
60. And perhaps several other things of this \ind could be discovered.
This statement seems to imply that Theophrastus was in favor of experiment, though perhaps it only shows that he thought that such technical processes were discovered by chance. It certainly does not show that he appreciated the importance of systematic experiment.
61. Among the substances obtained by mining there still remain those that are found in earth-pits.
This section serves as an introduction to the remainder of the treatise, which deals principally with the earthy minerals or with products derived from them.
The fundamental meaning of γεωφανής is "looking like earth." This suggests that Theophrastus may have been referring to substances "that have the appearance of earths." However, Liddell and Scott's lexicon states that in this particular passage the word means "a spot where a kind of ochre was dug." It seems clear that this definition has been taken from the translation given by
«»V, no (Wellmann ed., V, 95). *8° XXXIII, 123.
