164 THE PRINCIPLES OF SCIENCE. 



and Davy speaks of this discovery as the foundation of all 

 that had since been done in electro-chemical science. 



It is otherwise with the discovery of electro-magnetism, 

 or the relation between the magnet and electricity. 

 Oersted, in common with many others, had suspected the 

 existence of some relation between these strange powers, 

 and he appears to have tried to detect its exact nature. 

 Once, as we are told by Hansteen, he had employed a 

 strong galvanic battery during a lecture, and at the close 

 it occurred to him to try the effect of placing the con- 

 ducting wire parallel to a magnetic needle, instead of at 

 right angles, as he had previously done. The needle 

 immediately moved and took up a position nearly at 

 right angles to the wire ; he inverted the direction of the 

 current, and the needle deviated in a contrary direction. 

 The great discovery was made, and if by accident, it was 

 such an accident as happens only to those who deserve 

 them, as Lagrange remarked of Newton h . There was, in 

 fact, nothing accidental, except that, as in all totally new 

 discoveries, Oersted did not know what to look for. He 

 could not infer from previous knowledge the nature of 

 the relation, and it was only repeated trial in different 

 modes which could lead him to the right combination. 

 High and happy powers of inference, and not accident, 

 subsequently induced Faraday to reverse the process, and 

 show that the motion of the magnet would occasion an 

 electric current in the wire. 



Sufficient investigation would probably show that 

 almost every branch of art and science had an accidental 

 beginning. In historical times almost every important 

 new instrument, such as the telescope, the microscope, or 

 the compass, was probably suggested by some accidental 

 occurrence or observation. In pre-historic times the germs 

 of the arts must have arisen still more exclusively in 

 ll 'Life of Faraday/ vol. ii. p. 396. 



