62 ELECTROTYPE PROCESSES. 



solution, two or three shakes, or give the wire attached to it, while 

 the mould is in the solution, a smart tap with a key or knife, or any 

 thing convenient ; but the most certain means we have tried, is to 

 moisten the surface with alcohol just previous to putting it into the 

 copper solution. A little practice in these manipulations will soon 

 enable the student to avoid these annoyances. 



Deposition on large Objects. When busts or figures, whether of 

 wax or plaster of Paris, are to be coated with copper, with no other 

 conducting surface than black lead, it is attended with considerable 

 difficulty to the inexperienced electrotypist. The deposit grows over 

 all the prominent parts, leaving hollow places, such as armpits, neck, 

 &c., without any deposit ; and when once missed, it requires consi- 

 derable management to get these parts coated, as the coated parts 

 give a sufficient passage for the current of electricity. It is recom- 

 mended by some electrotypists to take out the bust, and coat the 

 parts deposited upon with wax, to prevent any further deposit on 

 them ; but this practice is not good, especially with plaster of Paris, 

 for an electrotype ought never to be taken out till finished. Some- 

 times the resistance of the hollow parts is occasioned by the solution 

 becoming exhausted from its position in regard to the positive 

 pole. In this case a change of position effects a remedy. It 

 may be remarked, that when a bust or any large surface having 

 hollow parts upon it, is to be electrotyped, as many copper connec- 

 tions as possible ought to be made between these parts and the zinc 

 of the battery. Let the connections with the hollow parts be made 

 with the finest wire which can be had, and let the zinc plate in the 

 cell have a large surface compared to the surface of the figure, and 

 the battery be of considerable intensity : if attention is paid to these 

 conditions, the most intricate figures and busts may be covered over 

 in a few hours. Care has to be observed in taking off the connec- 

 tions from the deposit, or the operator may tear off a portion of the 

 deposit : if the wires used are fine, they should be cut off close to the 

 deposited surface. 



To make Busts and Figures. Busts and figures, and other com- 

 plicated works of art, which cannot be perfectly coated with black 

 lead, may be covered by a film of silver or gold, which serves as a 

 conducting medium to the copper. This is effected by a solution 

 of phosphorous in sulphuret of carbon. The operation being 

 patented, we will take advantage of the description given of it in 

 the specification. " The solution of phosphorus is prepared by add- 

 ing to each pound of that substance 151bs. of the bisulphuret or 

 other sulphuret of carbon, and then thorougly agitating the mix- 

 ture; this solution is applicable to various uses, and amongst others, 

 to obtaining deposits of metal upon non-metallic substances, either 

 by combining it with the substances on which it is to be deposited, 



