74 Original Articles. [ Jan. 
power, though the telescope showed that the alteration in the lantern 
had taken place at the right time.” M. Reynaud estimates the usual 
intensity of the light at from 180 to 190 standard Carcel burners. 
This superiority of brightness is of practical service only in thick 
weather, for if the air be clear an ordinary first-class light under the 
old system answers every purpose of the mariner, and in fog no light 
is of any avail; but it scarcely requires demonstration that in certain 
intermediate states of the atmosphere, the brighter light will penetrate 
the haze, rain, or snow to a distance at which the other is perfectly 
invisible. There is nothing in the nature of the rays emitted to 
prevent its doing so, for when submitted to spectral analysis, the 
Electric light is found to contain every ray that the oil-flame does, and 
others beside. The returns of neighbouring lighthouse keepers, and 
of the masters of two of the lightships at the Goodwin Sands, during 
the experiment at the South Foreland, show this to be actually the 
case, and similar testimony is borne by the masters of passing vessels, 
the commanders of the Channel Steam Packets, and the pilots who 
frequent the neighbouring seas. 
The peculiar bluish colour of the light as seen from a distance is 
another advantage, by distinguishing it from ships’ lights, or lamps on 
shore; and practically this is a great object. Of course, it may be 
made red or green, or any other tint, by coloured glasses. Indeed it 
is peculiarly adapted for such a purpose. As the light can be 
interrupted and immediately rekindled with full intensity at pleasure, 
this light offers facilities for signaling which no other does. Hach 
lighthouse might be made to repeat its own number all night long, if 
that were thought desirable. Another advantage is well stated in the 
words of Professor Faraday :—‘ In cases where the light is from lamp 
flames fed by oil, no increase of ght at or near the focus or foci of 
the apparatus is possible beyond a certain degree, because of the size 
of the flames; but in the Electric lamp, any amount of the light may 
be accumulated at the focus, and sent abroad at, of course, an 
increased expense. In consequence of the evolution of the light in so 
limited a focal space, it may be directed seaward, diverging either 
more or less, or in a vertical or horizontal direction at pleasure, with 
the utmost facility. ‘The enormous shadow under the light, produced 
by the oil-flame burner, which absorbs and renders useless the 
descending rays to a very large extent, does not occur in the Mag- 
neto-electric lamp; all the light proceeding in that direction is 
turned to account. ‘The optical part of the arrangement, whether 
dioptric or reflecting, might be very small in comparison with those 
in use :” and, indeed, it is so at Dungeness. As there is always an 
extra steam-engine and machinery on the premises, and ready for 
work, the power, and the consequent light between the charcoal 
points, might at any time be doubled, if the state of the atmosphere 
seemed to require it. 
It has already been remarked that in fog no light, however power- 
ful, is of much avail, and public attention is now being directed to the 
necessity of improving our fog signals. It has been well observed in 
M. Reynaud’s Report, “‘ During foggy weather the supplementary steam- 
