434 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, ' 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, ' 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 1 4th 

 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. Eobert Sabine states 

 that Professor Wheats tone'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 the scientific 

 societies of England. 



