129 
The following paper was read at the Ordinary Meeting of 
the Society, held April 15th, 1873 : — 
“ O n some improvements in Electro-magnetic Induction 
Machines,” by Henry Wilde, Esq. 
Soon after the announcement by the author (in 1866) of 
the discovery that electric currents and magnets, indefin- 
itely weak, could, by induction and transmutation, produce 
magnets and currents of indefinite strength,* a number of 
electricians suggested other methods by which this principle 
could be exhibited and more powerful results obtained than 
those which the author described. The most interesting as 
well as the most useful of these suggestions was to augment 
the magnetic force of the elementary magnet, by transmit- 
ting the direct current from the armature of a magneto- 
electric, or an electro-magnetic machine through wires 
surrounding its own permanent or electro-magnet, in such 
a direction as to intensify its magnetism until, by a series 
of actions and reactions of the armature and the magnet on 
each other, an exalted degree of magnetism in the iron or 
steel was obtained. 
This idea seems to have occurred to several electro- 
mechanicians almost simultaneously in England, Germany, 
and America. In a letter to the EjigiyicsT newspaper of 
July 20th, 1866, Mr. Murray, after referring to the authors 
experiments, writes that he wishes to point out a variety of 
the principles embodied in the machine the author had 
described, which, he says, is so obvious that it cannot fail 
to be hit upon by some inventor before long, and warns 
anyone whom it may strike against patenting the idea, 
seeing that he had already constructed a machine upon the 
plan. Mr. Murray then states that, “Whereas Mr. Wilde, 
beginning with an ordinary magneto-electric machine, 
uses the current obtained from it to charge a powerful 
* Proceedings of the Royal Society, April 26, 1S66. Philosophical Trans- 
actions, Vol. clvii., 1867. Philosophical Magazine, S. 4, Yol. xsxiv. 
