Robert Boyle (“Philosophical Works,” London, 1738, Vol. I. p. 506, or London, 1744, Vol. III. p. 647) treats of different hypotheses advanced to solve the phenomena of electrical attraction, saying: “The first is that of the learned Nicholas Cabaeus (A.D. 1629), who thinks the drawing of light bodies by amber ... is caused by the steams which issue out of such bodies and discuss and expel the neighbouring air ... making small whirlwind.... Another is that of the eminent English philosopher, Sir Kenelm Digby (A.D. 1644), and embraced by the very learned Dr. Browne (A.D. 1646) and others, who believed that ... chafed amber is made to emit certain rays of unctuous steams, which, when they come to be a little cooled by the external air, are somewhat condensed ... carrying back with them those light bodies to which they happen to adhere at the time of their retraction.... Pierre Gassendi (A.D. 1632) thinks the same, and adds that these electrical rays ... get into the pores of a straw ... and by means of their decussation take the faster hold of it ... when they shrink back to the amber whence they were emitted ... Cartesius (Descartes, A.D. 1644) accounts for electrical attractions by the intervention of certain particles, shaped almost like small pieces of riband, which he supposes to be formed of this subtile matter harboured in the pores or crevices of glass.” The ancients were acquainted with but two electrical bodies--amber (_electron_), which has given the denomination of the science; and _lyncurium_, which is either the tourmaline or the topaz (Dr. Davy, “Mem. Sir Humphry Davy,” 1836, Vol. I. p. 309). From a recent article treating of gems, the following is extracted: “The name of the precious stone inserted in the ring of Gyges has not been handed down to us, but it is probable that it was the topaz, whose wonders Philostratus recounts in the Life of Apollonius. An attribute of the sun and of fire, the ancients called it the _gold magnet_, as it was credited with the power of attracting that metal, indicating its veins, and discovering treasures. Heliodorus, in his story of Theagenes and Caricles, says that the topaz saves from fire all those who wear it, and that Caricles was preserved by a topaz from the fiery vengeance of Arsaces, Queen of Ethiopia. This stone was one of the first talismans that Theagenes possessed in Egypt. The topaz, at present, symbolizes Christian virtues--faith, justice, temperance, gentleness, clemency.”