Lead . 
227 
E, a handle or winch, which, in the machine at large, 
may be a wheel communicating to mill-work, and thus 
turn the rollers BB. 
F, a pinion, fixed on the gudgeon of the upper roller, 
and communicating with a similar pinion on the arbor of 
the lower roller, keeping both of them in motion by the 
turn of the handle. As it is necessary that the upper ro!« 
ler should be at liberty to rise or fall, in order to give a 
due degree of pressure to the lead in passing between the 
rollers, two weights GG, with proper stems to them, are 
placed over the gudgeons of the upper roller, thereby 
keeping a due degree of pressure; and, if any piece of 
the lead should be thicker than usual, admitting the roll- 
er to give way to it, and thereby preventing any injury to 
the machinery. 
H, a notch in one side of the wooden vessel, serving to 
regulate the depth of the water on the riddles DDD, 
The foregoing description is accompanied by two cer- 
tificates; one from Mr. Samuel Walker Parker, stating 
that many tons of white lead have been made, in the man- 
ner above described, at the manufactory at Islington, be- 
longing to Walker, Ward, and Co. and that, since Mr. 
Ward’s plan was adopted, no other method has been used. 
The other certificate is from Mr. H. Browne, of Irongate, 
Derby ; who says, that he thinks the foregoing invention 
a very valuable improvement in preparing white lead, and 
that the quality of the lead is not in the least injured by it. 
Mr. Wetherill, of Philadelphia, obtained a patent for a 
somewhat similar contrivance.” 
The white lead, thus being scraped and rolled off from 
the blue lead, the latter is sent back to the smelting room, 
and the white lead agitated in water, then pumped up in- 
to other troughs to drain : the refuse of the first troughs 
is also conveyed to the smelting room. 
