It is scarcely credible, that the real cause of Electricity was known to the ancients, and yet there are indications of it in the work of Timæus Locrensis, concerning the soul of the world.
The moderns are also divided in their sentiments, as to how it happens that Rivers, continually flowing into the sea, do not swell the mass of waters, so as to make it overflow its banks. One of the solutions of this difficulty is, that rivers return again to their source by subterraneous passages or canals; and that there is, between the sea and the springs of rivers, a circulation analogous to that of blood in the human body. This solution, however, is the same as Seneca’s, who accounts for their not overflowing the bed of the ocean, by imagining secret passages, which reconduct them to their springs; and because, at their springs, they retain nothing of that brackishness which they carried with them from the sea, he supposes they are filtrated in their circuit through winding paths, and layers of every soil, so that they must needs return to their source as pure and sweet as they departed thence.
[462] We may with exactness determine what the true colour was of the purple of the ancients, by attending to two passages of Pliny, wherein he says, that the whole aim of the Tyrians and Phœnicians, in bringing their purple to the utmost perfection, was to render it in colour as like as possible to the oriental amethyst. Plin. Hist. Natur. lib. ix. c. 38 & 41, et lib. xxxvii. c. 9.
Hùc secundus ventus nunc est; cape modò Vorsoriam,
Stasime; cape Vorsoriam, recipe te ad Herum.
[464] With respect to what was known to the ancients, and of which we still are ignorant, recourse may be had to Pancirolus de rebus Deperditis, particularly to his first book, chap. i. 35, 36, 39, respecting the colour of purple, the ductility of glass and the effects of the ancient music. See especially Dion. Cassius’s History, in Tiber. lib. lvii. p. 617. E. Plin. lib. xxxvi. c. 26, &c. Isidor. de Originib. lib. xvi. c. 15, respecting the ductility of glass.