500 A New Era in Illumination. [ Oct., 
It is not our fault that they exist, but being in existence it has 
been our duty to expose them. We fervently hope that the visita- 
tion from Above, and the legislation of man, may have the effect, 
once for all, of sweeping from amongst us the nuisances and un- 
healthy conditions which decimate our large towns; and may they 
inculeate lessons of morality, sobriety, and cleanliness in the minds 
of the people. 
Ill. A NEW ERA IN ILLUMINATION.—WILDE’S 
MAGNETO-ELECTRIC MACHINE. 
By Wit11am Croorss, F.R.S. 
In the first number of this Journal an article “On Lighthouse 
Illumination by Magneto-electricity,” was contributed by Dr. Glad- 
stone. Nearly three years have elapsed since that time, and a very 
important result in this branch of Science haying recently been 
obtained, it seems a fitting opportunity again to draw attention to 
the subject, as an introduction to our more immediate topic. 
The experience of the last two or three years in the use of the 
electric spark in lighthouses has brought prominently forward 
several disadvantages and objections under which it labours. The 
advantages are many and obvious, and were well summarised in Dr. 
Gladstone’s article, and were amply sufficient to justify the English 
Authorities in persevering attempts to introduce this light into 
practice. In 1855, while corresponding on this subject with 
the late Hydrographer to the Admiralty, Admiral Washington, Mr. 
T. Stevenson stated, “What we want is powerful apparatus, 
not intricate distinctions. To be enabled to see a light m a thick 
night, though it be only half-a-mile further than at present, may be 
of incalculable moment. If therefore we can increase the power of 
our lights so as to make them pierce the gloom but that fraction of 
a mile further than they do at present, we are moving in the right 
direction. On that small amount of extra offing, hundreds of lives 
may depend.” It would appear as if the electric light was pre-emi- 
nently adapted to meet a case like this ; but, recently, doubts have been 
thrown on its superiority over oil in penetrating fog. In 1865, Mr. 
Berthon, the Secretary to the Trinity House, said, that, for a limited 
range of from nine to ten miles, the electric is immensely superior 
to any other light, but beyond that distance it appears to lose in a 
great degree its power, until at eighteen or twenty miles it is not 
very different to any ordinary first-class light; and Mr. Stevenson 
likewise states, that at great distances the oil light maintains its 
power better than the electric. Such a phenomenon certainly seems 
