380 SEC. 10. ELECTRICITY. 



e. Copper deposits removed. 



f. The same soldered together to form a metal " drum." 

 g. Moulds of the handle. 



h. Moulds with the copper deposited in them. 



i. Copper deposits removed from the moulds. 



j. The same soldered together as part of the tankard. 



h. A group of the other details of the tankard deposited in copper and 



removed from the moulds. 

 /. The tankard as soldered together and fitted with copper " drum," ready 



for gilding, &c. 

 91. Completed metal copy of the tankard, silvered and parcel gilt. 



1730b. Group of Perns, &c., in a basket, as an illustra- 

 tion of the method of coating natural objects, however delicate, 

 with copper, and afterwards silvering or gilding the same. 



The objects are first prepared with a metallic surface, then immersed in a 

 solution of sulphate of copper, and afterwards electro-plated with gold or 

 silver. 



1730c. Electro Jewellery. Gustave Trouve, Paris. 



1731. Single Cell Apparatus, used in the Electrotype 

 process. J. How and Co. 



This consists of a glass outer cell furnished with a perforated shelf, with 

 an upright porous vessel containing a zinc rod well amalgamated. The 

 porous cell is charged with dilute sulphuric acid, and the object to be coated 

 attached to the binding screw by a copper wire, and suspended in the outer 

 glass vessel, which is filled with a saturated solution of sulphate of copper, a 

 supply of crystals of this sulphate being placed upon the perforated shelf for 

 the purpose of keeping up the strength of the solution. 



Smee's Battery, used in the Electrotype process. 



J. How and Co. 



This consists of a central platinised silver plate for the negative element 

 between two zinc plates, connected together by a clamp. It is charged 

 with dilute sulphuric acid. 



1731a. DanielPs Constant Battery, used in the Electro- 

 type process. J. How and Co. 



The outer copper cell forming the negative element ; the positive element 

 consists of a rod of zinc placed in a porous cylinder. To charge the battery 

 the porous cell is filled with dilute sulphuric acid and the outer cell with a 

 saturated solution of sulphate of copper, crystals of the sulphate being placed 

 upon the perforated shelf of the outer cell for the purpose of keeping up the 

 strength of the solution. 



1731b. Bunsen's Battery, used in the Electrotype 

 process. J. How and Co. 



This consists of a negative element of carbon contained in a vessel of porous 

 earthenware, which is surrounded by a cylindrical zinc positive element in an 

 outer glazed earthenware cell. It is charged by placing concentrated nitric 

 acid in contact with the carbon, and dilute sulphuric acid in contact with the 

 zinc. The zinc is required to be kept well amalgamated. 



