[644] See end of B. xxviii.
[645] See end of B. ii.
[646] See end of B. viii.
[647] We now enter upon the Sixth division of Pliny’s work, containing an account of mineral substances of all descriptions.—Dr. Bostock.
[648] “Ipsæ opes.” The metals were looked upon by the ancients as the only true riches. It is in this sense that Ovid says, Metam. B. i.: “Effodiuntur opes, irritamenta malorum.” Pliny applies the term “pretia rerum” to metals, as forming the unit of value.
[649] Electrum is described in c. 23, as gold mixed with a certain quantity of silver. The word “electrum” is also used to signify amber, as in B. iii. c. 30.—B.
[650] “Æs;” by “æs” is here probably meant copper, as the author is speaking of what is dug out of the earth; it is more fully described in the first two Chapters of the [next] Book. According to the analysis of Klaproth, the æs of the ancients, when employed in works of art, cutting instruments, statues, vases, &c., was the “bronze” of the moderns, a mixture of copper and tin, in which the proportion of tin varied, from a little more than 2 to 1.14 per cent, according as the object was to procure a flexible or a hard substance. Agricola speaks of “æs” as synonymous with “cuprum,” and Pliny will be found several times in the present Book, speaking of “æs Cyprium,” meaning probably the finest kind of copper, and that without alloy.—B.
[651] Pliny has already referred to this topic in B. ii. c. 63.—B.
[652] Or shades below.
[653] “Illa quæ non nascuntur repente.”