238 
Iron. 
The preparation previous to melting is as follows :™ 
After the bottom of the furnace is laid, and smoothed 
with fresh sand, and all the openings made air-tight, the- 
furnace-man introduces a kindling at the teasing-hole, ac- 
companied with new pit-coal. In a few minutes a conside- 
rable volume of dark flame mixed with smoke is produc- 
ed. The fire quickly gathers strength ; more coal is intro- 
duced ; and the furnace now becomes filled with a yellow- 
coloured flame. By continuing this operation for an hour, 
or an hour and quarter, the furnace and flame will have 
become completely white ; the latter steady, and at times 
apparently without motion. The furnace-man now judg- 
es the bottom to have been sufficiently hardened for re- 
ceiving the pig-iron without any risk of sinking. The 
charging-door is now opened, and the pig-metal thrown 
carefully and regularly upon that part of the bottom for- 
merly described as being appropriated for its reception* 
The door is again closed and made air-tight, and the opera- 
tion of firing continued with unremitting care and attention. 
The time of melting depends entirely upon the quanti- 
ty of metal introduced. The furnaces described above 
are capable of melting from 50 to 60 hundred weight of 
metal each, and when there is a moderate circulation of 
air they will perform this work in 2 1-2 or 3 hours. In 
half an hour after the metal is introduced it assumes a 
blackish red colour. It then begins to brighten with 
every additional fire, and in about one hour appears white, 
and begins to lose shape, and resemble a wreath of snow. 
An eye accustomed to such heats will now discern the 
metal beginning to drop, and run down the inclined plane 
in very beautiful streamlets resembling quick silver. 
Eight or ten of these are visible at a time, and after pro- 
ceeding half way down begin to form junctions with each 
other, and flow connected into the general cavity or reser- 
voir. By-and-by this becomes filled, and literally forms 
