DESCARTES ON THE MAGNETIC FIELD. 



363 



imaginary spirals were urged were exactly mapped by the 

 iron filings, a purely physical observation. The chief 

 features of the field of force had been observed. The 

 route of new discovery now lay toward its properties. 



When Descartes reaches the electrics he shows some 

 unwillingness to formulate theories about them, as it were, 

 ex cathedra, as he had done in reference to the magnet. 

 It is necessary, he says, to u say something" about these 

 bodies the electrics it was not his original intention to 





DESCARTES' REPRESENTATION OF THE MAGNETIC FIELD. 1 



do so and then (lame and impotent conclusion for the 

 man whose mind was the reverse of the Baconian medal) 

 he is not fully certain why they act as they do until he 

 shall have made "several experiments to discover their 

 nature." Experiments! and by the apostle of deductive 



1 From his Principia Philosophise. This depicts a large spherical mag- 

 net (the earth) having its poles at A, B, with smaller magnets I, K, L, 

 M, N, disposed in inductive proximity The lines of force in which the 

 assumed spirals arrange themselves are clearly shown. 



