358 On the Manufacture of Tin-plate. 
of the business, as few men like to work in 
it; though I understand that a good Pickler 
is highly valued by his employers, and ob- 
tains great wages. It is necessary to notify 
that this, and the former process with the 
acidulated water, are both hastened by giv- 
ing to those menstrua an increase of tempe- 
rature—and this is effected by means of 
heated flues which run under each trough. 
Little additional heat is necessary in summer, 
however, as 90° or 100° of Fahrenheit is a 
temperature sufficiently high for either of 
these operations. 
When the plates come out of the pickle, 
they are put into pure water, and scoured in 
it with hemp and sand, to remove any re- 
maining oxide, or rust of iron that may be 
still attached to them, for wherever there 
is a particle of rust, or even dust upon 
them, there the tin will not fix; and they 
are then put into fresh water to be there pre- 
served for the process of tinning. The de- 
sign of putting the plates into pure water, 
after they come out of the sours, is to pre- 
vent their becoming again oxidated—for it 
has been found that after these operations, 
they will acquire no rest, although they should 
be kept twelve months immersed in water. ~ 
It will be perceived that all these processes 
