455 
to those who 'prepare White Lead . 
dusty white lead can rise in any part to the work-people* 
No such plan as this (although long desired) has, to my 
knowledge, been put in execution, so as to answer all 
the purposes above stated. It may be asked, why the 
lead in the common mode is not made wet before it is 
passed through the rollers and screen. Should this be 
done, the lead would be a paste on the rollers and screen, 
and the white lead prevented separating from the blue 
lead, which is absolutely necessary in the preparation of 
white lead. 
j Reference to the Engravings Plate 13. 
Fig. 1 , A, an inclined plane of wood, on which the 
white and blue lead is placed immediately from the 
stacks, and thus introduced between the brass rollers 
BE. 
CC, the vessel containing water. 
DDE, the pierced oak boards or riddles, which, by 
being made to slide in grooves in the sides of the vessel 
CC, may occasionally be taken out by removing the 
wooden bar ee . 
E, a handle or winch, which, in the machine at large, 
may be a wheel communicating to mill- work, and thus 
turn the rollers EE. 
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 
roller 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 GE, with proper stems to them, 
(as shown more at large in fig. 3,) are placed over the 
gudgeons of the upper roller, thereby keeping a due de- 
gree of pressure ) and, if any piece of the lead should be 
