174 



which Professor Ayrton had also alluded, 

 he might be allowed to mention that, in 

 the discussion of another paper by the 

 author, he had first stated the fact,* and 

 had described a simple experiment, show- 

 ing that the primary and secondary cur- 

 rents reached their maxima and minima 

 practically at the same time. 



Sir James N. Douglass considered that 

 the discussion had thrown a considerable 

 amount of light on the relative advan- 

 tages of direct and alternate-current ma- 

 chines for lighting and power purposes. 

 In 1862 the French lighthouse authori- 

 ties adopted the alternate-current machine 

 of the Alliance Company at the two light- 

 houses of Cape la Heve; and in 1866, 

 Holmes produced his alternate-current 

 machine, and a pair of these were made 

 for the Trinity House and exhibited at 

 the Paris International Exhibition of 

 1867. These machines were installed at 

 the Souter Point Lighthouse in 1870, 

 where they had worked regularly and 



* Journal of the Institution of Electrical Engineers, 

 vol. xvil., p. 215. 



