"The Western nations, the Greeks, and the Romans, knew that magnetism could be communicated for a length of time to iron ('sola hæc materia ferri vires à magneti lapide accipit, retinetque longo tempore.'--Plin., xxxiv., 14). The great discovery of the terrestrial directive force, therefore, depended alone on this, that no one in the West happened to observe that a longish piece of magnetic iron ore, or a magnetized iron rod, floated at liberty upon water by means of a piece of wood, or balanced and suspended freely in the air by means of a thread. But a thousand years and more before the commencement of our era, in the dark epoch of Codru, and the return of the Heraclidæ to the Peloponnesus, the Chinese had already magnetic cars, upon which the movable arm of a human figure pointed invariably to the south, as a means of finding the way through the boundless grassy plains of Tartary. In the third century, indeed, of the Christian era, at least 700 years, therefore, before the introduction of the ship's compass upon European seas, Chinese craft were sailing the Indian Ocean under the guidance of magnetic southern indication. This early knowledge and application of the magnetic needle gave the Chinese geographers great advantages over those of early Greece and Rome, to whom, for example, the true course of the Apennines and Pyrenees was never known. "Magnetism is one of the numerous forms in which electricity manifests itself. The ancient suspicion of the identity of electrical and magnetical attraction has been demonstrated in the present age. 'If electrum (amber),' says Pliny, in the sense of the Ionic natural philosophy of Thales, 'becomes inspired by friction and warmth, it attracts bark and dried leaves, exactly like the magnetic iron stone.'[215] The same words occur in the discourse laudatory of the magnet of the Chinese natural philosopher Kuopho, who lived in the fourth century. It was not without surprise that I myself observed, among the children at play on the woody banks of the Orinoco, the offspring of native tribes in the lowest grade of civilization, that the excitement of electricity by friction was known. The boys rubbed the dry, flat, and shining seeds of a creeping leguminous plant (probably a negretia) until they attracted fibers of cotton wool and chips of the bamboo. This amusement of these coppery children is calculated to leave a deep and solemn impression behind it. What a chasm lies between the electrical play of these savages and the discovery of the lightning conductor, of the chemically decompounding pile, of the light-evoking mechanical apparatus! In such gulfs, millenniums in the history of the intellectual progress of mankind lie buried."--Humboldt's _Cosmos_, vol. i., p. 180; Klaproth, _Lettre à M.A. de Humboldt, sur l'Invention de la Boussole_, p. 125. 1834.