DISCOURSE OF W. B. TAYLOR. 233 



he frequently expressed his strong conviction that a judicious code 

 of patent laws — if faithfully administered — furnishes the most 

 equitable method of recompensing meritorious inventors. The 

 institution was a good one — for others. 



The discovery of 3Iagneto-electricity . — From the magnetizing 

 influence of the galvanic current, physicists were almost inevitably 

 led to expect the converse reaction; and this anticipation appears to 

 have been co-eval with electro-magnetism. As early as 1820, the 

 illustrious Augustin Fresnel remarked: "It is natural to try 

 whether a magnetic bar will not produce a galvanic current in a 

 helical wire surrounding it;" and he made various experiments to 

 determine a question which was supposed to involve the soundness 

 of Ampere's theory. In November, 1820, he announced that 

 though he at first supposed his attempt at the magneto-electric 

 decomposition of water was partially successful, he was finally 

 satisfied that no decisive result was obtained.* 



Five years later, Faraday attempted the same experimental 

 inquiry ; and among his earliest publications gave an account of his 

 unsuccessful trials. After describing his arrangements he says : 

 "The magnet was then put in various positions and to different 

 extents into the helix, and the needle of the galvanometer noticed : 

 no effect however upon it could be observed. The circuit was made 

 very long, very short, of wires of different metals and diiferent 

 diameters, down to extreme fineness, but the results were always 

 the same. Magnets more and less powerful were used, some so strong 

 as to bend the wire in its endeavors to pass round it. Hence it 

 appears that however powerful the action of an electric current may 

 be upon a magnet, the latter has no tendency by re-action to diminish 

 or increase the intensity of the former; a fact which though of a 

 negative kind, appears to me to be of some importance."t 



Nor were American physicists discouraged by the records of re- 

 peated failures : and when the great Henry magnet was received 

 at Yale College, Professor C. U. Shepard (chemical assistant to 

 Professor Silliman) at once attacked the problem with this new 



*Annales de Chimie et de Physique, 1820, vol. xv. pp. 219-222. 



t Quarterly Journal of Science, etc. of the Royal Institution of Great Britain, July, 

 1825, vol. xix. p. 338. This well shows the danger of generalizing too broadly from 

 negative results. 



