NICKEL-PL ATING. 139 



through the hot sawdust. This oven is heated by means of an 

 iron worm tube 2 inches in diameter. 



The nickeling workshop properly speaking contains fourteen 

 vats, as follows : 



No. Capacity. 



1. Wooden box for heated sawdust 250 litres. 



2. Potash bath vat in ordinary cast iron .. .. 100 



3. Yellow copper bath vat in enamelled cast iron 100 



4. Experimental bath vat 20 



5. Eed copper bath vat 480 



6. Hot-water vessel 500 



7. . Stoneware nickel bath vat 300 



8. Stoneware nickel bath vat 200 



9. Wooden cold-water vessel 1000 



10. Stoneware scouring vessel 100 



11. Stoneware scouring vessel, whiting bath.. .. 100 



12. Wooden nickel bath vat 2000 



13. Stoneware nickel bath vat 150 



14. Enamelled cast-iron experimental bath vat .. 60 



The sawdust box 1 and the bath vats 2, 3, 5 and 6 are 

 heated to a temperature of 70 Centigrade by means of steam 

 pipes. 



Amongst the works executed in this factory, we will limit 

 ourselves to briefly describing the nickel-plating of sheet zinc. 



Nickel-plating of Sheet Zinc. The operations to be effected 

 are six in number, viz. : (1) the scouring of the rough sheets ; 

 (2) the polishing ; (3) the cleansing ; (4) the coppering ; (5) 

 the nickeling ; (6) the final polishing. 



1. Scouring. The sheets are cut to the required dimensions, 

 and put in piles on a special shelf; they are drilled in the 

 corners and near the edges with two holes for the suspending 

 hooks. 



The workman introduces an S shape hook into each hole, and 

 puts the sheet into the potassic bath No. 2, giving it an alternating 

 motion during the space of a few seconds. He then puts it into 

 the water tub No. 9, where he dips it two or three times so as 

 to remove the alkali. He afterwards puts it into the scouring 

 bath No. 10, where it is left one minute, to be thereafter put 

 into bath No. 11, and dried above vat No. 9. The sheet is 



