a basis. But he does not give such a classification, probably because he did not find it practicable. Instead, he suggests that it would be better to classify them according to color. This is another indication that the attitude of Theophrastus toward scientific problems tends on the whole to be more practical than that of his immediate predecessors, Plato and Aristotle, both of whom were more interested in the philosophical aspects of these problems than in their practical solution. Although Theophrastus suggests that earths should be classified according to color, he does not follow his own suggestion very closely in his discussion of the various kinds of earths. For example, the two red pigments, cinnabar and red ochre, are described in widely separated sections. Again, white lead is described in one section, and other white earthy substances are discussed much further on in the treatise. The truth is that Theophrastus does not seem to have found any systematic method of classifying what he calls earths, though some order is evident in his arrangement. Thus the two ochres, red ochre and yellow ochre, are treated together, probably because they are found together and are otherwise related. White lead and verdigris are mentioned one after the other, apparently because they were manufactured in a similar way. In reality, Theophrastus groups die earths according to similarities in their use, mode of occurrence, or method of manufacture, rather than according to their color.
The manuscripts do not contain any reference to location or environment; Wimmer substituted των τόπων ("places") for τους τούτων, following a conjecture by Schneider. And Turnebus expresses the same idea when he writes locorum succos in his Latin translation.
50. Moreover, some seem to have been set on fire and burnt, such as realgar and orpiment and others of the same hjnd. To put it plainly, all of these result from a dry and smoky exhalation.
As was explained in the notes on section 3, Theophrastus closely follows the ideas of Aristotle about the origin of earths,389 though
369 For further discussion of the similarity of the ideas of Aristotle and Theophrastus on the origin of mineral substances generally, and for remarks on the interpretation of this particular passage, cf. D. E. Eichholz, Classical Quarterly, XLIII (1949), 143-46.
