THE ELECTRIC LIGHT. G?l 
of February a paper from Sir Charles Wheatstone was 
received, 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 interaction 
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 magnet and armature to 
a magnetic intensity previously unapproached. Conceive 
the Siemens armature placed between the poles of a suit- 
able electro-magnet. Suppose this latter to possess at 
starting the faintest trace of magnetism; when the arma- 
ture rotates, currents of infinitesimal strength are generated 
in its coil. Let the ends of that coil be connected with 
the wire surrounding the electro-magnet. The infinitesimal 
current generated in the armature will then circulate round 
the magnet, augmenting 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 immediately brings its enhanced power to bear upon 
the coil. By this play of mutual give and take between 
magnet and armature, the strength of the former is raised 
in a very brief interval from almost nothing to complete 
magnetic saturation. Such a magnet and armature are 
able to produce currents of extraordinary power, and if an 
Sabine's statement; still it would be dangerous in the highest 
degree to depart from the canon, in asserting which Faraday was 
specially strenuous, that the date of a discovery is the date of its 
publication. Toward the end of December, 1866, Mr. Alfred Varley 
also lodged a provisional specification (which, I believe, is a sealed 
document) embodying the principles of the dynamo-electric machine, 
but some years 'elapsed before he made anything public. His 
brother, Mr. Cromwell Varley, when writing on this subject in 1867, 
does not mention him (Proc. Roy. 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. 
