156 ELECTROLYSIS. 



actually traversing a grave crisis. The foreigners who used to 

 make their purchases in Paris, where they were certain of find- 

 ing works combining taste, careful workmanship, and reasonable 

 prices, now prefer to purchase German articles copied from our 

 patterns, indifferently mounted, but of extremely low prices. Our 

 manufacturers are making great exertions in order to overcome 

 this crisis, and it is to be hoped that if they are not able to 

 entirely stave it off they will at least succeed in diminishing its 

 effects. 



The great desideratum is to continue to produce satisfactory 

 work and lower the prices without attempting to turn out 

 scamped articles, otherwise our reputation would die out with- 

 out any chance of being revived. 



A good solution for copper baths is recommended by Mr. 

 Watt, of New York. 



It is prepared by dissolving about 230 grammes of sulphate 

 of copper in 1 litre of hot water. Some ammonia (density '880) 

 is gradually added to the cooled solution, stirring well all the 

 time until the precipitate which was previously formed is dis- 

 solved in an excess of ammonia. A concentrated solution of 

 potassic cyanide is then poured in until the blue colour of am- 

 moniacal sulphate of copper disappears ; it is even desirable to 

 leave an excess of cyanide ; the bath is used at a temperature 

 of 50 to 55 Centigrade. 



Before being put into the bath, the pieces of zinc must be 

 dipped into the alkaline bath and then scoured in : 



Water 10 litres. 



Sulphuric acid 450 grammes. 



They are then passed through the sand. 



M. Eoseleur's formula slightly differs from the preceding 

 one ; it is as follows : 



