466 Process for liefining Lead. 
shall be left flush with the bottom of the frame or 
cross bars, otherwise in fixing the test to its situation 
at the bottom of the furnace it would be liable to be 
bulged. 
Fixing the Test in its situation. 
The rim of the test is now to be plastered with clay 
or moistened ashes, placed upon the supporting cross 
bars, and fixed with wedges firmly against the bot- 
tom of the furnace, the breast next to the feeding 
hole. 
A gentle fire may now be lighted, and gradual- 
ly increased until the test be red hot. When it 
ceases to emit steam from the under side it is sufficient- 
ly dry. 
Lead previously melted in the iron pot f is ladled 
into the test until the hollow part be nearly filled, the 
operator closes the feeding aperture, and increases the 
heat of the furnace until the surface of the lead is well 
covered with litharge ; he then removes the door from the 
feeding hole, and with an iron rod, which has one end 
bent down at right angles about three inches and made 
flat or chissel- shaped, scrapes the small gutter or chan- 
nel o until the litharge just flows into it, the blast from a 
pair of double bellows is then directed from the back 
part over the surface of the test, the litharge is urged for- 
ward, and flows from the gutter upon the floor of the re- 
finery ; the operation now goes forward, gradually adding 
lead as the escape of litharge makes necessary, until the 
gutter is so worn down that the test does not contain 
more than an inch in depth of lead, the blast is then 
taken off, the gutter filled up with moistened ashes, and 
a fresh one made on the other side the breast; the test is 
again filled, though not so full as at first, and the opera- 
tion carried on until this gutter also is worn down and the 
