244 ® n ^ e Component Parts of Iron-JioneS . 



In the prefent mode of preparing iron-ftones, too much 

 is left to chance and the difcretion of fubordinate workmen. 

 The furface of the piles, being always in contact with the 

 open air, is frequently expofed to perforations from winds, 

 efpecially in thofe parts where the layer of ignited coab 

 comes in contact with the current : a hollow fpace is foon 

 formed ; the fuel, by means of the frefh air continually 

 pouring in, becomes ignited to whitenefs ; the furrounding 

 ftone is immediately fufed : fhould this aperture be joined 

 by a fimilar communication from oppofite fides of the fire, 

 a degree of heat will be excited beyond what could have 

 been conceived poflible in this mode of burning, and oxy- 

 gen be combined with a mafs of ftone in fuch an high pro- 

 portion as to form a very confiderable part of the whole 

 weight. This is an accident which will take place even 

 where order, regularity and experience are confpicuous s 

 were it poffible to avoid it by torrefying the iron-ftone ill 

 that juft temperature which has been formerly demonftrated 

 as the moft proper, uniting at fame time an equal degree of 

 economy, it would contribute greatly to reduce to certainty 

 and rule the operations of the fmelting- furnace. 



The extreme of fufing the materials, and combining the 

 iron with an extra portion of oxygen, is not the only evil 

 which an accurate mode of torrefa&ion would avoid : the 

 fame train of cafualty often affords a confiderable portion of 

 the ftone not enough prepared, and fome quite untouched 

 bv the fire. The effects produced by iron-ftone in this ftatc 

 are exactly fimilar to thofe experienced in the former, arifing 

 from the fame caufe, but exifting as the refult of two oppo- 

 fite extremes* 



I confefs it is much eafier to point out the faults of an 

 eftabliihed mode of practice, than to fubftitute one, which, 

 though it might unite fome fuperior advantages, yet might 

 •not combine an equal number upon an extended fcale. I 

 have frequently confidered the fubjecl, and have as often 

 been imprefled with the truth of its importance in the ma- 

 nufacturing 



