GILBERT OF COLCHESTER. 343 



experiments of Hertz, we must still admit that the ultimate nature of 

 electricity remains wrapped in mystery. It is true, we discard the 

 material effluvium of Gilbert, but only to substitute for it an ethereal 

 ripple, a quiver, a wave motion in the hypothetical ether with which we 

 fill all space. 



From 15S0 to 1600, we find Gilbert spending in his workship all the 

 leisure he can snatch from his professional duties. He notes down his 

 experiments, his failures as well as his successes, discusses them, reasons 

 on them, and pursues his inquiry further and further. In a word, we 

 find him toiling in his workshop at Colchester as Faraday toiled more 

 than 200 years later in the low, dark rooms of the Eoyal Institution of 

 Great Britain. Both were actuated by the same calm, persevering, ex- 

 perimental spirit. Gilbert founded and christened the science of elec- 

 trics ; he left it in its infancy, it is true ; but with sufficient vitality to 

 enable it to survive the neglect of years, until at last it was taken up 

 and fondly cared for by our Franklins and Faradays. 



III. 



The science of magnetism is even more indebted to Gilbert than that 

 of electricity. The ancients spoke of the lodestone as the Magnesian 

 stone, from its being found in Magnesia, in Asia Minor. Gilbert con- 

 stantly uses the adjective magnetica; and it is to his use of that word 

 that we owe the terms magnet, magnetic and magnetism.* He showed 

 that a great number of bodies could be electrified; but he maintained 

 that those only could exhibit magnetic properties which contain iron. 

 He satisfies himself of this by rubbing with a lodestone such substances 

 as wood, gold, silver, copper, zinc, lead, glass, etc., and then floating 

 them on corks, quaintly adding. that they show 'no poles, because the 

 energy of the lodestone has no entrance into their interior.' 



To-day we know that nickel and cobalt behave like iron, whilst 

 antimony, bismuth, copper, silver and gold are susceptible of being 

 influenced by powerful electromagnets, showing what has been termed 

 diamagnetic phenomena. Even liquids and gases, in Faraday's classical 

 experiments, yielded to the influence of his great magnet ; and Professor 

 Dewar, in the same Eoyal Institution, exposed some of his liquid air 

 and liquid oxygen in the presence of the writer to the influence of 

 Faraday's electromagnet and found them to be strongly attracted, thus 

 behaving like the paramagnetic bodies, iron, nickel and cobalt. 



Gilbert observes in all his magnets two points, one near each end, 

 in which the force, or, as he terms it, 'the supreme attractional power,' 

 is concentrated. He terms these poles by analogy to the earth ; and he 

 will have it understood that these poles are not mathematical points, as 



* According to Humboldt, "the barbarous word magnetismus" was intro- 

 duced in the eighteenth century. 



