Iron* 239 
a beautiful molten miror, in which sometimes part of the 
| interior furnace is reflected* 
The furnace-man, by searching at the bridge with his 
fire-iron or teaser, judges when the metal is nearly all 
gone. Of this he is certain by looking up from the peep- 
hole of the lading- door. If the streamlets of the running" 
metal have ceased, then the whole is melted, and ready 
for running out. 
In the operation of melting, the three following circum- 
stances ought to be particularly attended to : the thinness 
or hotness of the metal ; the waste or loss sustained in 
melting ; and the quantity of coals employed. 
The first is of the utmost importance, as many articles 
in the foundery business require the metal in a state of the 
greatest division ; otherwise they will be found imperfect 
when taken from the sand, and unfit for sale. The fur- 
nace-man, therefore, is always on the watch to replace the 
fire as it decays, and keep a large and sharp volume of 
flame constantly passing over the metal. 
The waste or loss of real metal is also an object of great 
importance. This always bears a relation to the quality 
of the iron, the strength and cleanness of the coals, and the 
judgment and attention of the melter. Strong iron is 
found always more difficult to fuse ; this necessarily ex- 
poses it for a long period in contact with the flame. The 
reverse happens with metal that is more fragile, and easier 
broken in the pig. The length of the exposure in fusing 
depends on this ; and other circumstances being alike, the 
loss or waste of metal will also be in the same ratio. 
There are, however, other facts not unworthy of notice. 
No. I. pig-iron, or richly carbonated metal, when run 
from an air-furnace, will be found in point of quality little 
better than No. II. or carbonated iron. This is owing 
to a quantity of its carbon being destroyed during the fu- 
sion. The loss in melting No, L iron, therefore, chiefly 
