327 
ON THE RELATION 
OF SCIENCE TO ELECTRO-PLATE MANUFACTURES. 
BY GEORGE GORE. 
PAET I. 
L ITTLE did Gay Lussac think when he discovered cyanogen, 
in the year 1815, the great influence which that substance 
would have upon the comforts and luxuries of every-day hfe. 
Prussian blue, the substance with which laundresses colour 
linen, and which is composed of cyanogen and iron, was, it is 
true, known as long ago as the year 1704, when it was dis- 
covered by Diesbach and Dippel, in Berlin ; but that this 
substance contained cyanogen was not known until Gay Lussac 
discovered it. 
All experimental knowledge generally passes through three 
- stages, — viz., discovery, invention, and practical daily working : 
a philosopher discovers some new fact or principle in nature ; 
an inventor applies it to some useful purpose ; and a man of 
business brings the invention before the public, and continues 
it in daily use. 
Suppose that Gay Lussac had not discovered cyanide of 
potassium, and that it had never been discovered, it is highly 
probable that the manufacturing returns of Birmingham, Shef- 
field, and other places in which electro-plating is conducted, 
would be much less in amount at the present time than they 
are, simply because there is no other known substance with 
which the electro-plating of base metals with gold and silver 
can be satisfactorily effected. 
The base of every article which is coated with a thin film of 
silver for domestic purposes by electro-plating, consists of an 
alloy of three metals — copper, zinc, and nickel ; this substance, 
commonly called nickel silver or German silver, is chosen for 
this purpose, because it possesses a white colour nearly allied 
to that of real silver; and when the outer coating of noble 
metal is worn away by use, the exposed baser portions do not 
present the unseemly appearance that they would if a metal or 
alloy of another colour, such as copper or brass, had been used. 
Nickel was discovered by Cronstedt in the year 1751, and 
