182 COSMOS. 



The brilliant discoveries of Oersted, Arago, and Faraday 

 have established a more intimate connexion between the 

 electric tension of the atmosphere and the magnetic tension of 

 our terrestrial globe. Whilst Oersted has discovered that 

 electricity excites magnetism in the neighbourhood of the 

 conducting body, Faraday's experiments have elicited electric 

 currents from the liberated magnetism. Magnetism is one of 

 the manifold forms under which electricity reveals itself. The 

 ancient vague presentiment of the identity of electric and 

 magnetic attraction has been verified in our own times. 

 " When electrum (amber)," says Pliny, in the spirit of the 

 Ionic natural philosophy of Thales,* " is animated by friction 

 and heat, it will attract bark and dry leaves, precisely as the 

 loadstone attracts iron." The same words may be found in 

 the literature of an Asiatic nation, and occur in a eulogium 

 on the loadstone by the Chinese physicist, Kuopho.f I 

 observed with astonishment, on the woody banks of the Ori- 

 noco, in the sports of the natives, that the excitement of 

 electricity by friction was known to these savage races, who 

 occupy the very lowest place in the scale of humanity. 

 Children may be seen to rub the dry, flat and shining seeds or 

 husks of a trailing plant (probably a Negretia) until they are 

 able to attract threads of cotton and pieces of bamboo cane. 

 That which thus delights the naked copper-coloured Indian is 

 calculated to awaken in our minds a deep and earnest im- 

 pression. What a chasm divides the electric pastime of these 

 savages from the discovery of a metallic conductor, discharg- 

 ing its electric shocks, or a pile composed of many chemically 



* Of amber (succinum, glessum) Pliny observes (xxxvii. 3.), " Genera 

 ejus plura. Attritu digitorum accepta caloris anima trahunt in so paleas 

 ac folia arida quee levia sunt, ac ut magnes lapis ferri ramenta quoque.* 

 (Plato, in Timceo, p. 80. Martin, Etude sur le Tim&e, t. ii, p. 343-345. 

 Strabo, xv., p. 703, Cusaub. ; Clemens Alex., Strom., ii., p. 370, where sin- 

 gularly enough a difference is made between TO vov\iov and TO rjXiKrpov.) 

 When"Thales, in Aristot. de Anima, 1, 2, and Hippias, in Diog. Laert., 

 i. 24, describe the magnet and amber as possessing a soul, they refer only 

 to a moving principle. 



f " The magnet attracts iron as amber does the smallest grain of 

 mustard-seed. It is like a breath of wind which mysteriously penetrates 

 through both, and communicates itself with the rapidity of an arrow." 

 These are the words of Kuopho, a Chinese panegyrist on the magnet, 

 who wrote in the beginning of the fourth century. (Klaproth, Lettre & 

 M. A. de Humboldt, sur V Invention de la Boussole, 1834, p. 125.) 



