70 Original Articles. | Jan. 
LIGHTHOUSE ILLUMINATION BY MAGNETO- 
ELECTRICITY. 
By J. H. Guapsronz, Esq., Ph.D., F.R.S. 
Anyone who, on a tolerably clear night, has crossed the channel be- 
tween Folkestone and Boulogne, and remained on deck, must have . 
noticed on the French coast what appeared a brilliant star, now 
waxing, now waning. It was the light of the far-famed Pharos, on 
Cape Grisnez. But if he has made the passage within the last 
eighteen months, his gaze will have been attracted by a still brighter 
star on the British coast, of a bluish tint, steady and_ brilliant. 
This is the Magneto-electric Light at Dungeness, the brightest spark 
in the world, and one which unites a rare scientific with a practical 
interest, and may prove only the first lighted of a multitude of similar 
beacons. I propose to say a few words on the history, production, 
and merits of this Light. 
History.—If we ask the parentage of the Magneto-electric Light, 
Mr. Frederick Hales Holmes is certainly its father, but, like other 
beings, it has had two grandfathers—the philosopher who first showed 
the conducting power of charcoal, and the brilliancy of the light 
between charcoal terminals of an interrupted galvanic current; and 
Professor Faraday, who discovered that when a piece of soft iron, 
surrounded by a coil of metallic wire, was made to pass by the poles 
of a magnet, an electric current was produced in the wire, which 
revealed its existence by effecting chemical decompositions, or by 
giving a spark. This spark, it is true, was barely visible as at first 
obtained, but it has been exalted into the present Magneto-electric 
Light. 
“Tt appears that in 1853 some large Magneto-electric machines were 
erected in Paris for producing gas by the decomposition of water, 
the object of the proprietor being to use this gas for the purposes of 
combustion ; but the scheme failed, the Company that was being 
formed came to nothing, and the machines were pronounced by leading 
scientific men to be only expensive toys. Mr. Holmes, however, who 
was one of the referees, proposed to turn them to account for electro- 
plating and gilding, and thought it possible that the Electric Light 
might be produced advantageously by their means. ‘‘ My proposi- 
tions,” he says, in his evidence before the Royal Commission on Lights, 
Buoys, and Beacons, “were entirely ridiculed, and the consequence 
was, that instead of saying that I thought I could do it, I promised 
to do it by a certain day. On that day, with one of Duboscq’s regu- 
lators or lamps, I produced the Magneto-electric Light for the first time, 
but as the machines were ill-constructed for the purpose, and as I had 
considerable difficulty to make even a temporary adjustment to produce 
a fitting current, the Light could only be exhibited for a few minutes at 
a time—say ten or twenty minutes—when the adjustments were entirely 
displaced by the friction ; the rubbing surfaces were worn away. From 
this time I directed my attention more particularly to the reconstruc- 
