430 FRAGMENTS OF SCIENCE. 



entirely abandoned ; alternating currents instead of the 

 direct current being employed. M. Serrin modified his 

 excellent lamp with the express view of enabling it to 

 cope with alternating currents. During the Interna- 

 tional Exhibition of 1862, where the machine was shown, 

 M. Berlioz offered to dispose of the invention to the 

 Elder Brethren of the Trinity House. They referred 

 the matter to Faraday, and he replied as follows : ' I 

 am not aware that the Trinity House authorities have 

 advanced so far as to be able to decide whether they 

 will require more magneto-electric machines, or whether, 

 if they should require them, they see reason to suppose 

 the means of their supply in this country, from the 

 source already open to them, would not be sufficient. 

 Therefore I do not see that at present they want to 

 purchase a machine.' Faraday was obviously swayed by 

 the desire to protect the interests of Holmes, who had 

 borne the burden and heat which fall upon the pioneer. 

 The Alliance machines were introduced with success at 

 Cape la Heve, near Havre ; and the Elder Brethren of 

 the Trinity House, determined to have the best avail- 

 able apparatus, decided, in 1868, on the introduction of 

 machines on the Alliance principle into the lighthouses 

 at Souter Point and the South Foreland. These 

 machines were constructed by Professor Holmes, and 

 they still continue in operation. With regard, then, to 

 the application of electricity to lighthouse purposes, the 

 course of events was this : The Dungeness light was 

 introduced on January 31, 1862 ; the light at La Heve 

 on December 26, 1863, or nearly two years later. But 

 Faraday's experimental trial at the South Foreland 

 preceded the lighting of Dungeness by more than two 

 years. The electric light was afterwards established at 

 Cape Grisnez. The light was started at Souter Point 

 on January 11, 1871 ; and at the South Foreland on 



