William Gilbert 5 



speculations he travelled beyond the justifiable limits of his 

 experimental facts. 



In his electrical researches Gilbert had the same -wide 

 outlook. Amber, when excited by friction, was known to 

 attract light bodies ; why he asked himself should special 

 properties be confined in one case to iron and in another to 

 amber? He tried but failed to find a magnetic action on 

 water and other bodies, but discovered that the property 

 of amber was shared by a large number of substances, 

 such as glass, sulphur, and the precious stones. He was 

 the first to note that electric effects persist longer in dry 

 air than in wet weather, that an electrified body loses its 

 power when moistened with water or spirit, or when glowing 

 coal is brought near to it. We also owe to him the word 

 " electricity " (derived from " fj\fKrpov ", the Greek word for 

 amber) ; though only in the form of the adjective. " Vim 

 illam," he writes, " electricam nobis placet appellare, 

 quse ab humore provenit." In a posthumous work he 

 declares himself to be an adherent of the Copernican 

 doctrine, and shows a clear scientific perception, as when 

 he explains that there is no intrinsic property of " levity," 

 but that when light bodies are seen to ascend they do so 

 under the influence of the pressure of the surrounding 

 heavier bodies. 



Galileo, 1 almost the only man of science born in the 

 sixteenth century who stands on an intellectual level with 

 Gilbert, appreciated his work. In the third of the famous 

 " Dialogues " he gives an account of it, and Salviati, the 

 imaginary person who is made to express Galileo's own 

 views, mentions Gilbert's book, " which might not have 

 come into my hands if a peripatetic philosopher had not 

 presented it to me, for the reason, I believe, that he did 

 not wish to contaminate his own library with it." After 

 referring to some of Gilbert's experiments, Salviati further 

 says : 



" I highly praise, admire, and envy this author for 



having formed such a stupendous conception on a 



1 The name is given in its usual form, but it sounds rather like 

 calling a man Thomas whose full name is Thomas Thomasson. Galileo's 

 father was Vincenzio Galilei; his own full name Galileo Galilei. 



