504 A New Era in Illumination. [ Oct., 
to Magnet 2, &c., or from induced current No. 1 to induced current 
No. 2, &c., multiplies the power very many times,* it will not be 
considered surprising that after three involutions the induced 
current possesses such magnificent powers. 
Some erroneous opinions are pretty generally entertained as to 
the actual discovery claimed by Mr. Wilde, and the splendour of 
the result, for achieving which he deserves the very highest credit, 
is liable to cause earlier investigators in the field to be over- 
looked: this would be most unfair, for it is through thei in- 
strumentality that the way has been paved for the success now 
achieved. In 1838 the Abbés Moigno and Raillardt proved that 
by taking an electro-magnetic machine, the original magnet of 
which would only support a few grammes, and passing the electric 
current generated by it round a large electro-magnet, the latter 
could be made to support a weight of 600 kilogrammes. The 
Abbés carried the multiplication of power only so far as to obtain 
the more powerful magnet No. 2 from the weak magnet No. 1. 
Electro-magnets of extraordinary power, with coils arranged 
longitudinally instead of transversely on their armatures, had been 
made by Mr. Joule. Magneto-electric machines with revolving 
armatures, in which electro-magnets had been substituted for per- 
manent magnets, had been constructed by Dr. Page and Professor 
Wheatstone. Magneto-electric machines had been made to act on 
electro-magnets in various telegraphic instruments by Wheatstone, 
and subsequently by others; and Dr. Page, as well as the experi- 
mentalists above mentioned, had observed the important fact that 
an electro-magnet excited by a magneto-electric machine became 
capable of effects greatly exceeding those of the original magnet. 
The peculiarly constructed armature employed by Mr. Wilde is 
likewise essentially identical with Siemens’ helix, a full description 
of which may be seen in Siemens’ patent, and also in the fifth 
volume of Du Moncel’s ‘Applications de lHlectricité,’ page 249, 
published in 1862. It is, however, right to say, that Mr. Wilde, in 
his patent of February 25, 1863, expressly states that he makes no 
claim to the peculiar construction of the armature. 
By the kindness of Mr. Wilde we are enabled to give our readers 
a full description, with drawings, of the machine now in process of 
manufacture for the Northern lighthouse. Fig. 1 represents a side 
view, and Fig. 2 an end view of the machine; the letters referring 
to the same parts in each: a aaaa are 16 permanent magnets, 
bolted on to the magnet cylinder b, shown in magnified section at 
Fig. 3. The magnets weigh about 5 lbs. each, and will support a 
weight of about 20 lbs. In the magnet cylinder the part b d is 
* We say very many, but we have absolutely no data to guide us to a near 
approximation. F 
+ Moigno’s ‘ Télégraphie Electrique, p. 15, Paris, 1849, 
