142 Account of the 



pose, is first cut to the necessary length, and then rolled at the 

 mill, by a process which is peculiar to this manufacture, into 

 plates of the requisite thinness, and of such form as is suitable 

 for the business. These plates are then cut by hand-shears to 

 the sizes suitable to the different markets. And as the shearer 

 shears the plates, he piles tliem in heaps, occasionally putting 

 one plate the cross way, to keep each box separate. Two hun- 

 dred and twenty-five plates are called a box, but they are not 

 put into boxes of wood in this stage of the operation. The iron 

 plates now go into the hands of the scaler, who takes them from 

 the shear-house, and bends each of them singly across the mid- 

 dle, into this form \, preparatory to their being cleaned for 

 tinning, and for the conveniency of putting them into the scal- 

 ing furnace, as will be more fully explained hereafter. 



This furnace, or oven, is heated by fiame thrown into it from 

 a fire-place of a peculiar construction, and it is this flame that 

 scales the plates, which are put into the oven in rows, and ar- 

 ranged three in each row, until the oven is full. It will be ob- 

 vious that if they lay flat on the floor of the oven, the flame 

 could play only on one side of each plate, whereas, by being 

 bent in the form already described, the flame can operate equally 

 on both sides. It may here be remarked that the form of all 

 tin-plates, one sort excepted, is that of a parallelogram, and that 

 if a piece of stiff paper, or paste-board, 13^ inches long, and 10 

 inches wide, be bent in the centre at an angle of about sixty de- 

 grees, and then put to stand on the two ends, we shall have the 

 form of a plate No. 1. properly bent for the scaling oven. 



The operation of cleansing, as it is called, and which is pre- 

 paratory to the process of scaling, is commenced by steeping the 

 plates for the space of four or five minutes, in a mixture of mu- 

 riatic acid and water, in the proportion of four pounds of acid to 

 three gallons of water. This quantity of the diluted acid will 

 generally be sufficient for eighteen hundred plates, or eight 

 boxes of 225 plates each. 



When the plates have been steeped for the time prescribed, 

 they are taken out of the liquor, and placed upon the floor, three 

 in a row, and then by means of an iron rod put under them, they 



