1879O «V$ Practical Results in London . 291 
by the rapid consumption of zinc in the battery was reduced 
to a minimum by the application of Faraday’s great disco- 
veries in magnetic electricity by Holmes, who made the first 
offer of his machine to the Brethren of the Trinity House 
in 1857, an( l their ultimate acceptance of it for lighthouse 
purposes on the recommendation of Faraday formed a 
new era in the history of the light. 
The next important step in the development of the subject 
was the great increase of magneto-eleCtric force obtained by 
means of the Siemens armature, in which the wire was 
wound longitudinally instead of transversely. Perhaps the 
most important step of all was the discovery — made appa- 
rently independently by Siemens, Wheatstone, and Varley — 
that the small amount of magnetic force contained in every 
bar of wrought-iron was capable, by aCtion and reaction, of 
producing heating and lighting effects far superior to those 
obtained with artificial magnets. Another difficulty, the 
expense involved in having to provide a certain number of 
artificial magnets which were constantly losing strength, 
was now done away with, the cost of the current being 
thereby still further reduced. 
In 1876 M. Denayrouze startled his colleagues of the 
French Academy by laying before them an invention of a 
young Russian officer which he designated an electric candle. 
Until then no one had thought of keeping the tips of the 
carbons always at the proper distance by placing them side 
by side. This was the most simple form of lamp yet in- 
vented ; there was no clockwork to get out of order ; there 
were no trains of wheels to stick when they ought to move ; 
no delicate but capricious magnets; but simply a couple of 
brass sockets, with a double-stemmed candle, consisting 
of two rods of carbon separated by a seam of kaolin, thrust 
into them. 
This is neither the place nor the time to inquire whether 
the Jablochkoff candle is better or worse than any other 
form of eleCtric lamp. Be this as it may — and the truth 
can only be arrived at after long experience — the J ablochkoff 
candle was the means of bringing the question of electrical 
illumination before the world in a very prominent manner. 
It was first applied in Paris to the illumination of the show- 
room of the Magasins du Louvre and the adjoining court- 
yard, the Place and Avenue de l’Opera, and the Hippodrome, 
thereby becoming the most prominent system of eleCtric 
lighting known to the general public. From Paris its fame 
spread to London, and within the last three or four months 
its capabilities for public use have been put to the test in 
the metropolis in four different places — the Thames Em- 
