432 FRAGMENTS OF SCIENCE. 



But the discovery which, above all others, brought 

 the practical question to the front is now to be con- 

 sidered. On the 4th of February, 1867, a paper was 

 received by the Royal Society from Dr. William 

 Siemens bearing the title, f On the Conversion of 

 Dynamic into Electrical Force without the use of 

 Permanent Magnetism*' l On the 14th of February a 

 paper from Sir Charles Wheatstone was received, bear- 

 ing the title, c 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 ex- 

 periments, 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 inter- 

 action 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 horse-shoe, for example that does not 



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.' 



1 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 ' Engineering,' No. 622, p. 45, Mr. Kobert 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. Towards 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 prob- 

 ably marks a national trait, that sealed communications, though 

 allowed in France, have never been recognised by thj 

 England, 



