ELECTROPLATING AND ELECTROTYPINa. 181 



bath, be carefully washed in boiling water. They are afterwards 

 washed and brushed in cold water, and then dried and rubbed 

 with turpentine. If they are not immediately used a layer of 

 melted wax should be spread on their surface. 



Messrs. Christofle & Co. exhibited in 1881, in Paris, some 

 very curious electros on which the steeling had been replaced 

 by nickeling, not by the surface nickeling, which would have 

 had the inconvenience of obliterating the lines of the engraving, 

 but by direct galvanic reproduction of nickel rendered thicker 

 by the galvanic backing of the electro. These electros were 

 obtained from a gutta-percha mould, on which a slight coating of 

 nickel, strengthened by a copper backing, had been deposited ; 

 they were mounted like ordinary copper galvanic electrotypes. 



