ON THE SCIENCE OP ELECTRO-PLATING. 41 
new method they were first cast of the requisite shape in Ger- 
man silver, and then coated with the precious metals, whereas 
by the old plan they required to be made from flat sheets of 
copper previously plated with silver by fusion; the different 
parts of a complex figure were first stamped into the requisite 
forms separately, and then the various pieces soldered together 
to make the entire figure ; and thus a figure which could be 
made entire in a single piece by the new mode, required to be 
formed of several or many pieces by the old one, and after a 
moderate amount of wear the lines where the parts were soldered 
together became visible, and greatly disfigured the object, and 
those lines could not again be covered with silver. By the old 
plan, every portion of a figure which was “ undercut,” i.e. in 
which the external parts overhung the internal ones, as the 
mouth or ear of an animal, for example, required to be made of 
several pieces, whilst by the new method such parts could be 
made entirely in one piece, with the whole figure, and be coated 
with the precious metals all over, without any seam or joining. 
A great scope for the extension of beauty and taste in designs 
of metallic figures and vessels thus commenced, which has gra- 
dually extended itself to electro-plated articles of very moderate 
price, such as tea-pots, coffee-pots, cream-jugs, sugar-basins, &c., 
the base of which consists of Britannia metal; and the electro 
process has thus enabled persons of limited incomes to enjoy 
the use of articles of elegant design previously inaccessible even 
to the wealthy. 
The next event of importance in the history of electro-plating 
consisted in the application of magneto-electricity instead of 
electricity from a voltaic-battery to depositing purposes. In 
August, 1842, J. S. Woolrich took out a patent for the use of 
a magneto-electric machine instead of a voltaic battery for 
electro-plating. This machine, which is in use at Mr. Fearn’s 
electro-gilding works, Birmingham, and various other places, 
consists of a revolving wheel containing at its outer edge a 
number of short bars of soft iron, upon which are wound coils of 
insulated copper wires, giving to the bars the appearance of a 
series of reels ; the wheel is surrounded by a set of powerful 
steel magnets, which are immovable, and fixed in a case, and 
have their ends, or poles, all pointing towards the wheel, so that 
as the wheel revolves, each of the reels of wire with its iron 
core, passes in succession between and veiy close to the poles 
of each magnet. As each of these coils approaches a magnet, a 
current of electricity is developed in one direction, and as it 
leaves the magnet a current is produced in the opposite direc- 
tion, and similarly Avith the whole of the coils. All the cor- 
responding ends of the coils are connected with the axle 
of the AAdieel, from which the positive electricity of all the 
