GILBERT OF COLCHESTER. 341 



rubs and brings near his versoriiim glass, sulphur, opal, diamond, 

 sapphi^-e, carbuncle, rock-crystal, sealing-wax, alum, resin, etc., and he 

 finds that all these attract his suspended needle, and not only the neeiille, 

 but everything else. His words are remarkable: 'Ad electrica feruntur 

 omnia.'* Here is a great advance on the amber and jet, the only two 

 bodies previously known as having the power to attract 'straws, chaff 

 and twigs,' the usual test-substances of the ancients. Pursuing his in- 

 vestigations, he finds a class of bodies which perplex him, because when 

 nibbed they do not affect his electroscope. Among these he enumerates : 

 bone, ivory, marble, flint, silver, copper, gold, iron, even the lodestone 

 itself. The former class he called electrica, electrics, deriving the term 

 from eUMron, the Greek name for amber; the latter class he termed 

 anelectrica, non-electrics. 



Science therefore owes to Gilbert the terms electric and "electrical ; 

 the term electricity was a coinage of a later period, due probably to the 

 illustrious Irish philosopher, Eobert Boyle, who uses the term in his 

 work On the Mechanical Production of Electricity, published in 1675. f 

 Gilbert never uses electricitas, but speaks of corpora electrica, effluvia 

 electrica, attractio electrica, motus electricus and the like. Had Gil- 

 bert chosen the Latin name for amber, succinum, as he might have 

 done, we should not be speaking to-day of electricity, electrostatics, 

 electro-optics, electrics, dielectrics; but should probably be using suc- 

 cinic for electric, succinical for electrical, succinicity for electricity, 

 together with a series of harsh-sounding derivatives and compounds. 



As we said, Gilbert was perplexed by the anomalous behavior of his 

 anelectrics. He toiled and labored hard to find out the cause. He 

 undertook a long, abstract, philosophical discussion of the nature of 

 bodies which, from its very subtlety, failed to reveal the cause of his 

 perplexing anomaly. Gilbert failed to discover the distinction between 

 conductors and insulators, and, as a consequence, never found out that 

 similarly electrified bodies repel each other. Had he but suspended an 

 excited stick of sealing-wax, what a promised land of electrical wonders 

 would have unfolded itself to his vision ! and what a harvest of results 

 such a reaper would have gathered in ! He noticed the effect of distance ; 

 for he says, 'The nearer the electric is to the versorium, the quicker is 

 the attraction.' It was reserved, however, for the French mathematician 

 and engineer, Coulomb, to show in 1785 that the law of attraction or re- 

 pulsion between two electrified particles varies inversely as the square 

 of the distance between them. 



From solids, he proceeds to examine the behavior of some liquids, 

 and finds that they too are susceptible of electrical influence. He 

 notices that a piece of excited amber when brought near a drop of water 



* All things are drawn to electrics. 



t To Boyle we are. also indebted for the name barometer. 



