288 PROCEEDINGS OF SECTION B. 
After the first 15 charges have been put in, 10 bars of lead are 
dropped into the furnace; after the next 15 charges, 10 bars 
more ; after the next 25 charges come 10 bars of lead ; and for, 
say, 90 charges afterwards, 1 bar of lead is fed in with each’ 
charge. This is done to get a lot of lead into the crucible quickly, 
for this additional lead, being heated to bright redness in its descent 
in the furnace, accordingly raises the temperature of the lead in 
the well or crucible, and stops the risk of the lead “freezing up” 
which we first saw melted in. 
While the men are filling up the furnace, you see that the 
tuyeres are all closed on the furnace, so taat no gases from the 
wood can get into the main blast-pipe and cause damage by 
exploding ; “that all the jackets are keeping cool and the ‘‘siphon” 
from the lead well to the outside of the furnace is not choked 
up and has a bright fire on it. In fact, give a look around 
to see that nothing is missing or wrong, so that the blast may 
be turned on the instant the furnace is filled up. With the - 
wood and coke which were first put in, 40 of the blowing-in 
charges fill the furnace to within 6 feet of the feed floor. 
Then, sending all the slag men down to their proper stations, 
the blast is turned on at a pressure of about 3 to 4 oz. to the 
square inch. In a very few minutes every joint between the 
water-jackets is smoking, if they have not been well rammed with 
fire-clay. 
Wet clay is placed on the smoky places to check it, because 
after a while these streams of smoke catch fire, and sometimes 
burn the windbags ; and, if they do not, the smoke from wood is 
not the most pleasant substance to get into one’s eyes. 
About twenty minutes after the blast has been turned on, the 
smoke all ceases, through the furnace beginning to smelt the 
charges which have just been put in; the first slag formed chilling 
on the jacket and closing the cracks. Then the tuyeres are 
examined frequently to judge how the slag is forming. In an 
hour and a quarter to one and one-half hours after the blast goes 
on, the first slag can be tapped from the furnace. The slags first 
produced by the furnace are purposely made lower in silica 
than those produced when in regular work; for, being low in 
silica, the newly blown-in furnace will be able to melt» them 
easily and quickly, and so get a good start. As a rule the first 
slag contains about 30 per cent. of silica. When the last of 
the 100 blowing-in charges are in the furnace the regular charge 
is put on. 
The following charges, with slags from same, together with the 
dip, sample assays, and mattes made, will give some idea of the 
usual composition of the smelting char ges when in regular work. 
The last eight are selected because sulphide of lead was used in 
large quantities and no carbonate of lead ore. 
