454 FRAGMENTS OF SCIENCE 



of February a paper from Sir Charles Wheatstooe was re- 

 ceived, bearing the title, "On the Augmentation of the 

 Power of a Magnet by the reaction thereon of Currents 

 induced by the Magnet itself. " Both papers, which dealt 

 with the same discovery, and which were illustrated by 

 experiments, were read upon the same night; viz., the 

 14th of February. It would be difficult to find in the 

 whole field of science a more beautiful example of the in- 

 teraction of natural forces than that set forth in these two 

 papers. You can hardly find a bit of iron you can 

 hardly pick up. an- old horseshoe, for example that does 

 not possess a trace of permanent magnetism; and from 

 such a small beginning Siemens and Wheatstone have 

 taught us to rise by a series of interactions between mag- 

 net and armature to a magnetic intensity previously un- 

 approached. Conceive the Siemens armature placed be- 

 tween the poles of a suitable electro- magnet. Suppose 

 this latter to possess at starting the faintest trace of mag- 

 netism; when the armature rotates, currents of infinitesi- 

 mal strength are generated in its coil. Let the ends of 

 that coil be connected with the wire surrounding the 

 electro- magnejt. The infinitesimal current generated in 

 the armature will then circulate round the magnet, aug- 

 menting its intensity by an infinitesimal amount. The 

 strengthened magnet instantly reacts upon the coil which 

 feeds it, producing a current of greater strength. This 

 Current again passes round the magnet, which immedi- 

 ately brings its enhanced power to bear upon the coil. 



of the dynamo-electric machine, but some years elapsed before he made any- 

 thing public. His brother, Mr. Cromwell Varley, when writing on this subject 

 in 1867, does not mention him (Proc. Eoy. Soc., March 14, 1867). It probably 

 marks a national trait, that sealed communications, though allowed in France, 

 have never been recognized by the scientific societies of England. 



