i;8 THE ADDRESSES, LECTURES, ETC., OF 



probable that such a monopoly will be able to maintain itself in 

 the long run against that irrepressible spirit of British enterprise, 

 which, though languishing at the present time of unparalleled 

 depression, is likely to reassert itself before long. 



Electricity has hitherto rendered service as the swift agency by 

 which our thoughts are flashed to great distances, but it is gradually 

 asserting its right also as a means of accomplishing results where 

 the exertion of quantitative effects are required. Much has been 

 said about the application of electricity for producing light, and 

 the French Company Alliance, as well as the Gramme Company, 

 have it is known for some years been establishing magneto-electric 

 apparatus to illuminate the lighthouses upon the French coast, and 

 for galvano-plastic purposes. 



By an ingenious combination of two magneto-electric machines, 

 with Siemens armatures, Mr. Wilde, of Manchester, succeeded in 

 greatly augmenting the effects produced by purely mechanical 

 means, but the greatest impulse in this direction was given in 

 1866-67 by the introduction of the dynamo-electrical principle, which 

 enables us to accumulate the current active in the electric circuit 

 to the utmost extent permissible by the conductive capacity of the 

 wire employed. Dr. Tyndall and Mr. Douglass, chief engineer to 

 the Trinity Board, in reporting lately to the Elder Brethren upon 

 the power of these machines and their applicability to lighthouses, 

 give a table showing that a machine weighing not more than 

 3 cwt. is capable of producing a light equal to 1,250-candle power 

 per horse-power expenditure of mechanical energy. Assuming 

 that each horse-power is maintained with an expenditure of 3 Ibs. 

 of coal per hour (which is an excessive estimate) it would appear 

 that one pound of coal suffices to maintain a light equal to 417 

 normal candles for one hour. The same amount of light would 

 be produced by 139 cubic feet of gas of 18-candle power, for the 

 production of which 30 pounds of coals are consumed. Assuming 

 that of this quantity, after heating the retorts, &c., 50 per cent, is 

 returned in the form of gas- coke, there remains a net expenditure 

 of 15 pounds of coal in the case of gas-lighting to produce the 

 effect of one pound of fuel expended in electric lighting, or a ratio 

 of 15 to 1 in favour of the latter. Add to the advantages of 

 cheapness in maintenance, and of a reduced capital expenditure in 

 favour of the electric light, those of its great superiority in quality 



