442 THE INTELLECTUAL RISE IN ELECTRICITY. 



as a piece of iron placed in the lodestone's field becomes 

 itself a magnet by induction, these lines extend through 

 the intervening space between the stone and the iron. 



Now turn to Newton, remembering that it was the 

 action-at-a-distance theory which confronted him as the 

 current explanation of attraction. He says: 



"That gravity should be innate, inherent, essential to 

 matter, so that one body may act upon another at a dis- 

 tance through a vacuum, without the mediation of any- 

 thing else by and through which their action and force 

 may be conveyed from one to another, is to me so great an 

 absurdity that I believe no man who has in philosophical 

 matters a competent faculty of thinking can ever fall into 

 it. Gravity must be caused by an agent acting constantly 

 according to certain laws; but whether this agent be ma- 

 terial or immaterial, I have left to the consideration of my 

 readers. m 



Again and again Faraday quotes this passage. As Tyn- 

 dall says, 2 he loved to do so. 



He found from it, to use his own words, that Newton 

 was "an unhesitating believer in physical lines of gravi- 

 tating force." 3 But in his co-ordination of electricity, 

 magnetism and gravity under the law of action and reac- 

 tion, Newton makes himself even clearer as to this, than 

 in the passage which Faraday selects. For what is the 

 imaginary rope connecting the two bodies and contracting 

 to draw them together but the direct expression of a phy- 

 sical line, not only of gravitating, but of electric and mag- 

 netic force? He not only sustains the last indirectly, as 

 Faraday seems to intimate, but directly. 4 



'Third Letter to Dr. Bentley. Horsley: Opera. London, 1782, vol. 

 iv., p. 438. 



2 Tyndall: Faraday as a Discoverer. N. Y., 1873. 



8 Exp'l. Researches, 3305. Dec., 1854. Jan., 1853, vol. iii., 507. 



4 "The attractive virtue (of magnetic bodies) is terminated nearly in 

 bodies of their own kind that are next them. The virtue of a magnet is 

 contracted by the interposition of an iron plate and is almost terminal 



