670 FRAGMENTS OF SCTENCtt. 
In 1866 a great step in the intensification of induced 
currents, and the consequent augmentation of the magneto- 
electric light, was taken by Mr. Henry Wilde. It fell to 
my lot to report upon them to the Royal Society, but 
before doing so I took the trouble of going to Manchester 
to witness Mr. Wilde's experiments. He operated in this 
way: starting from a small machine like that worked in 
your presence a moment ago, he employed its current to 
excite an electro-magnet of a peculiar shape, between 
whose poles rotated a Siemens armature;* from this arma- 
ture currents were ootained vastly -stronger than those 
generated by the small magneto-electric machine. These 
currents might have been immediately employed to produce 
the electric light; but instead of this they were conducted 
round a second electro-magnet of vast size, between whose 
poles rotated a Siemens armature of corresponding 
dimensions. Three armatures therefore were involved in 
this series of operations: first, the armature of the small 
magneto-electric machine; secondly, the armature of the 
first electro- magnet, which was of considerable size; and, 
thirdly, the armature of the second electro-magnet, which 
was of vast dimensions. With the currents drawn from 
this third armature, Mr. Wilde obtained effects, both as 
regards heat and light, enormously transcending those 
previously known. f 
But the discovery which, above all others, brought the 
practical question to the front is now to be considered. 
On the 4th of February, 1867, a paper was received by the 
Royal Society from Dr. William Siemens bearing the title, 
" On the Conversion of Dynamic into Electrical Force 
without the use of Permanent Magnetism." J On the 14th 
* Page and Moigno had previously shown that the magneto-electric 
current could produce powerful electro-magnets. 
f Mr. Wilde's paper is published in the " Philosophical Trans- 
actions" for 1867, p. 89. My opinion regarding Wilde's machine 
was briefly expressed in a report to the Elder Brethren of the Trinity 
House on May 17, 1866: " It gives me pleasure to state that the 
machine is exceedingly effective, and that it far transcends in power 
all other apparatus of the kind." 
\ A paper on the same subject, by Dr. Werner Siemens, was read 
on January 17, 1867, before the Academy of Sciences in Berlin. In 
a letter to Kngineering, No. 622, p. 45, Mr. Robert Sabine states 
that Professor Wheatstone's machines were constructed by Mr. Stroh 
in the months of July and August, 1866. I do not doubt Mr. 
