On the Manufacture of Tin-plate. 361 
increases the affinity of the iron for the tin, 
or, as they express it, that it makes the iron 
plates take the tin better. 
It is curious that burnt grease, or any kind 
of empyreumatic fat, effects this purpose bet- 
ter than pure fresh tallow. 
Another pot, which is fixed by the side of 
the tin-pot, is filled with grease only ; and in 
this the prepared plates are immersed, one 
by one, before they are treated with the tin ; 
and when the pot is filled with them, they 
are suffered to remain in it so long as the su- 
perintendant thinks necessary. If they re- 
main in the grease an hour, they are found 
to tin better than when a shorter time is al- 
lowed them. 
- From this pot they are removed, with the 
grease still adhering to them, into the pot 
just before spoken of, which contains the body 
of melted tin; and in this they are placed 
in a vertical position. Three hundred and 
thirty-eight, or three hundred and forty plates 
are usually put into this pot at once ;* and 
* 
* It is immaterial how many plates are put into the tin- 
pot at once—but this number is usually fixed upon, because 
it amounts to about one box and a half of plates; though, 
as they are put in edgewise, it is necessary the pot 
VOL. III. — ZZ 
