Faraday's discovery, which opens out the prospect of our being able to apply the electric light to public use.
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;[1] from this armature currents were obtained 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: 1. The armature of the small magneto-electric machine; 2. The armature of the first electro-magnet, which was of considerable size; and, 3. 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.[2]
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 Mr. William Siemens, bearing the title, "On the Conversion of Dynamic into Electrical Force without the Use of Permanent Magnetism."[3] On the 14th of February a paper from Sir Charles Wheatstone was received, bearing the title, "On the Augmentation of the Power of a Magnet by the
- ↑ Page and Moigno had previously shown that the magneto-electric current could produce powerful electro-magnets.
- ↑ Mr. Wilde's paper is published in the "Philosophical Transactions" 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 the 17th of May, 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 the 17th of January, 1867, before the Academy of Sciences in Berlin. In a letter to "Engineering," 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. 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 ("Proceedings of the Royal Society," 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.
