Iron . 
m 
and soon thoroughly heats and glazes the surfaces of the 
fire- stone* Shortly after this it rises to a level with the 
notch in the dam-plate, and by its own accumulation, to- 
j gether with the forcible action of the blast, it flows over. 
Its colour is at first black ; its fracture dense, and very 
ponderous ; the form it assumes in running off is flat and 
branched, sometimes in long streams, and at other times 
less extensive. If the preparation has been well conduct- 
ed, the colour of the cinder will soon change to white; and 
the metal, which in the state of an oxyde formerly colour- 
ed it, will be left in a disengaged state in the furnace* 
When the metal has risen nearly to a level with the dam, 
it is then let out by cutting away the hardened loam of 
the fauld, and conveyed by a channel, made in sand, to its 
proper destination ; the principal channel, or runner, is 
called the $ 07 V, the lateral moulds are called the pigs. 
In six days after the commencement of blowing, the 
furnace ought to have wrought herself clear , and have 
! acquired capacity sufficient to contain from 5000 to 7000 
j weight of iron. The quality ought also to be richly car* 
jbonated, so as to be of value and estimation in the pig- 
1 market. At this period, with a quality of coal as formerly 
! mentioned, the charge will have increased to the following 
proportions 5 baskets coaks, 4001b.; 6 boxes iron- 
stone, 3361b. ; 1 box limestone, 1001b. (Mushet.) 
In 1 Repertory of Arts, old series, is Mr. John Wih 
j kinson’s patent for a small furnace for smelting iron, but 
j I have not heard that it was ever adopted. 
The articles, Blast, Blow, Furnace and Iron, in Rees'S 
new Encyclopaedia, are well drawn up, mostly from the 
same sources that I have resorted to. As I have made 
little or no use of those articles, I refer to them here as 
worth perusing. 
The next plate, is the ground plan and outlines of the 
furnace commonly used in Pennsylvania. The plate it 
