438 Sir James N. Douglass [March 15, 



by the Trinity House at Blackwall, under the direction, and to the 

 great delight, of their scientific adviser, Faraday ; and after a series 

 of experiments, the satisfactory report of Faraday encouraged the 

 Trinity House to order a practical trial of a pair of the Holmes 

 machines. The trial was made at the South Foreland high lighthouse, 

 by Faraday and Holmes, on the 8th of December, 1858, when electricity 

 w^as found to be a formidable rival to oil and gas for lighthouse 

 illumination, and this position it maintains to the 23resent day. The 

 trials of this arc light were made at the focus of the first order dioptric 

 apparatus for oil light, which was very imperfect for the purpose, but 

 they w^ere sufiiciently encouraging to lead the Trinity House, under 

 the advice of Faraday, to proceed further with the electric light for 

 lighthouses. Faraday thus wrote in his report to the Trinity House : 

 " I beg to state that, in my opinion. Professor Holmes has practically 

 established the fitness and sufficiency of the magneto-electric light 

 for lighthouse purposes, so far as its nature and management are 

 concerned. The light produced is powerful beyond any other that 

 I have yet seen so applied, and in principle may be accumulated to 

 any degree; its regularity in the lantern is great, its management 

 easy, and its care there may be confided to attentive keepers of the 

 ordinary intellect and knowledge." These truly j)rophetic words of 

 Faraday have been entirely realised ; electricity still stands foremost 

 in the illumination of our coasts, and aj)pears destined to be one of 

 the greatest blessings ever conferred on humanity, and more esj)ecially 

 on '' those who go down to the sea in shijjs." On the 1st of February, 

 1862, Holmes's machines and aj)i3aratus for the electric liglit were 

 installed at Dungeness lighthouse, and in 1863 the French lighthouse 

 authorities followed, by an installation of the Alliance Comj)any's 

 magneto-electric machines and apparatus for fixed lights, at each of 

 the two lighthouses at Cape La Heve. We have here the first dioptric 

 apparatus designed and manufactured by Messrs. Chance Bros. & Co. 

 of Birmingham, for the electric fixed light at Dungeness. We have 

 also one of the Holmes lamps emj)loyed there. The lamp used at the 

 previous experiments was devised by M. Duboscq, of Paris. This lamp 

 of Holmes is similar to those of Duboscq and Serrin, excepting that the 

 upjDcr and low^er carbons and holders are balanced and regulated 

 through pulleys and small catgut cords, instead of by rack and 

 pinions. The carbons are ^-inch square, and the mean intensity of 

 the light in the arc was 670 candle units nearly. We have here 

 samples of the carbons employed from time to time in the develop- 

 ment of the electric light in lighthouses ; we have also aBergot lamp, 

 fitted with the fluted form of carbons I have recently devised. They 

 are of the dimensions now in use at the Saint Catherine's lighthouse, 

 and are giving a mean intensity in the arc of 40,000 candle units. 

 Cylindrical compressed carbons were soon manufactured for the electric 

 light, and were found to be more homogeneous in quality and the 

 flickering of the light less than with the original square carbons, 

 which were simply sawn from the residual carbon of gas retorts ; but 



