' Air ufed hi the BIqfi- Furnace. ili 



m&y be viewed as it oozes from the ore in fmall globular 

 niafles, frequently on fire, changing its ftate to that of an 

 oxvd. The combination of oxygen, by altering its denfity, 

 makes it fubjecl to the rc-a6lion of the blaft, \vhi<L-h at times 

 gives it a direcliofi from the tuyre with confiderable violence. 

 Thofe parts of the iron (by far the greateft) thus oxydated, 

 which efcape not at the tuyre, mix along with the fufed 

 earths of the ores and limeftonc, alter their colour, and flow 

 from the furnace more unrevivcd than at tlieir firft intro- 

 duftion. It is, however, very diflercnt, even with this in- 

 ferior quality of coal, where the denfity of the blaft is pro- 

 portioned to the inflammability of the fuel. Qualities and 

 quantities of crvide iron may be produced from this, equal 

 to thofe from coals reckoned of a fuperior nature. The 

 metal becomes as highly faturatcd witli carbonic prin- 

 ciple as that made from clod or fplint coal. The layie 

 evinces that decompofition is cB'cfted in Its proper place. 

 The fluid mafles of iron, as they become exprelTed from 

 the ore, are fhivorcd into fpray, before the denfe column 

 of air, without exhibiting the lead fymptom of decompo- 

 Ijtion. Thev again unite under the level of the blaft, in- 

 creafe in fize, and fink through the fluid llratum of eartlis to 

 the bottom of the furnace. This fact holds out one of the 

 ftrongeft proofs of the great afiinity wiiich carbon and iron 

 mutually poUefs towards each other. In the cafe of the iron 

 fcparating in an oxygenated ftate deftitute of carbon, it imme^ 

 diately falls a prey to its affinity for uxvgen. In the latter 

 cafe, the iron, being completely carbonated, refills decompo- 

 lition by the facrifice of a very fmall portion of its carbon : 

 it further proves, that the aflinitv of oxvgen is greater to 

 carbon than to 'iron; and that, before iron becomes o:4y- 

 datcd, all the carbon is taken up. 



The continuity of the particles of fplint coals renders the 

 cokes of difficult combuflion, capable of withftanding a moft 

 powerful difcharge of air, in qaantity and in the degree of 

 coriipreflion, withcut entailing effe<!:l;s fimilar to thofe pro- 

 duced with the ufe of fofter coals : this renders the opera- 

 tions with fplint coal lefs fubjeft to cafiialty and to chano-e. 

 Carbonated iron with a proper blaft is more uniformly-<^b- 

 uined, and frequently a very fuperior quantity. Similar 



efteag 



