1863. | Wilde’s Magneto-electric Machine. 503 
accordingly obtained from Messrs. Wilde, and their offer was at 
once accepted. 
The light from Messrs. Wilde’sl arge machine, which Mr. Steven- 
gon saw, is the most powerful artificial ight which has ever been 
produced, giving about eight times the light of the magneto-electric 
machines now in operation, and it was therefore not considered 
desirable to suggest the use at present of that sized machine for light- 
house purposes. A machine about half the power of the large one 
was recommended, as by a simple arrangement the brilliancy of the 
light, and the power required to drive the machine, could be varied 
at pleasure, to suit the different conditions of the atmosphere, and 
with it requirements could be met which would be beyond the 
power of any other description of machine. The dimensions of such 
a machine would be—length 64 inches, width 20 inches, height 
48 inches, and the cost 1,0007. Ultimately a machine of half this 
power, to cost 500/., was decided upon, and when the writer had the 
pleasure of visiting Messrs. Wilde’s workshops, and the advantage of 
listening to the inventor’s lucid description of his large machine, 
the one being made for the Commissioners of Northern Lighthouses 
was far advanced towards completion. 
Like most practical applications of science, the important results 
which Mr. Wilde has obtained, depend more upon an ingenious 
combination of several known facts, united with considerable 
engineering skill, than upon any really new and striking discovery 
in the science. The principle of the machine can be expressed in 
a few words. It consists in the application of the current from 
an electro-magnetic machine, armed with permanent magnets, for 
the purpose of exciting a powerful electro-magnet; this electro- 
magnet being now used as the basis of a still larger electro-magnetic 
machine, for the purpose of having induction currents generated by 
its agency. In other words; by well-known means, an electric 
current can be obtained by the rotation of an armature close to 
the poles of a magnet. If this electric current be passed round an 
electro-magnet, it may be made to produce a far greater amount of 
magnetism than was possessed by the first magnet. There is no 
difficulty, therefore, in comprehending how, by the mere interposi- 
tion of a rotating armature, and the expenditure of force, a small 
and weak magnet may be made to actuate a very powerful magnet. 
But as the power of the magnet increases, so does the power increase 
ot the electric current which may be generated by induction in an 
armature rotating between its poles. We have therefore only to 
pass this No. 2 induced current from No. 2 magnet round a still 
larger magnet No. 3, and by rotating an armature between its poles 
we can get a still more energetic induced current No. 3. Theo- 
retically there is no limit to this plan; it is a species of involution ; 
and when it is considered that each conversion from magnet No. 1 
