270 FRAGMENTS ^OF SCIENCE 



he writes, in 1831, "been desirous of discovering new facts 

 and new relations dependent on magneto-electric induction 

 than of exalting the force of those already obtained, being 

 assured that the latter would find their full development 

 hereafter." The labors of Holmes, of the Paris Alliance 

 Company, of Wilde, and of Gramme, constitute a brilliant 

 fulfilment of this prediction. 



But, as regards the augmentation of power, the greatest 

 ^tep hitherto made was independently taken a few years 

 ago by Dr. Werner Siemens and Sir Charles Wheatstone. 

 Through the application of their discovery a machine en- 

 dowed with an infinitesimal charge of magnetism may, by 

 a process of accumulation at compound interest, be caused 

 so to enrich itself magnetically as to cast by its perform- 

 ance all the older machines into the shade. The light now 

 before you is that of a small machine placed downstairs, 

 and worked there by a minute steam-engine. It is a light 

 of about 1,000 candles; and for it, and for the steam-engine 

 that works it, our members are indebted to the liberality of 

 Dr. William Siemens, who in the most generous manner 

 has presented the machine to this Institution. After an 

 exhaustive trial at the South Foreland, machines on the 

 principle of Siemens, but of far greater power than this 

 one, have been recently chosen by the Elder Brethren of 

 the Trinity House for the two lighthouses at the Lizard 

 Point. 



Our most intense lights, including the six- wick lamp, 

 the Wigham gas light, and the electric light, being intended 

 to aid the mariner in heavy weather, may be regarded, in 

 a certain sense, as fog- signals. But fog, when thick, is 

 intractable to light. The sun cannot penetrate it, much less 

 any terrestrial source of illumination. Hence the necessity 



