f 396 = 
als l \ 
Xv Ontive ribatidl Pro}ortions of Coals and Ir on-Stones wfed 
at the Blafi-Furnace, and of their proper-Application tor 
Ue. By Mr. Davip Musuet, of the Clyde Iron- 
Works. | Communicated by the Author. i : 
i bint i oe 
] N the fmelting operation a juft proportion and affociation 
of materials and mechanical conftruction ought to be blended 
in order to produce the ‘belt’ poffible ‘effets. Under the 
former are comprehended the cokes, iron-ftone, limeftone, 
and blaft; ‘by the latter 1s underftood the furnace, the power 
of the blowing-machine, or the compreffion and velocity 
under which the air is difcharged into the furnace, and the 
genius or mechanical’ fkill. of ‘the workmen. According to 
this divifion T fhall endeavour to point out the very various 
effets which difproportion in: any, cafe produces, and vice 
verfa. 
"In the preceding papers the coal and iron-ftone Hate siden 
traced through their various ftages of preparation, and that 
fare pointed out in whicly they were moft fuitable for the 
pieabte manufacture of the metal. It will be neceffary to 
¢earry‘along with us this fact, that m the exact proportion 
which the quantity of carbon bears to’ the quantity of metal 
in the ore, and its mixtures, fo will be the fufibility, and of 
courfe the’value of the pig-iron obtained. The importance 
of this truth will ftill farther appear when we confider the 
very various qualities of pit-coal, the different proportions of 
carbon which they contain, and the various properties at- 
. tached to every fpecies of this ufeful combuftible. 
Amons the many ftrata of coal which I have diftilled, 
fome TF have found to contain 70 parts in the roo. This 
large proportion is peculiar to the clod-coal, ufed at fome 
of the iron-works in England, and juftly preferred, for 
the purpofe of manufacture, to the purelt and hardeft variety 
of fplint-coal. - The latter I have found to average from 560 
to 59 parts of carbon, in the 100; and the foft, or mixed 
qualities of’coal, from’ 45 to 53 parts. ‘Such vatious propor- 
tions of carbon plainly point out, that the operations to be 
followed at’each individual iron-work ought not to reft upon 
7 precedent, 
