*$ On the ManufdBurc rf MalUahh Iron.- 



new line of manrfacture, before a good quality of product ?c 

 obtained. Thcic are fcldom diminifhed, but often increafed, 

 in transferring it from the fcale of experiment to that of ma- 

 nufacture. 



In the prefent procefs followed out at the bar-iron forges 

 in this country, the greeted drawback upon the profits and 

 corrc&nc'^ of the bufinrfs is the immenfe lofs of metal. 

 This is called wafte, and it is generally believed that the more 

 the wafte the better the quality of the refulting iron. This 

 circumftance I conceive is owing to the following facts — 

 tb r ' combustibility of the metal, the high temperature requi- 

 fite, and the tedious length of the procefs. The puddling 

 procefs invented by Cortes avowed a degree of finiplicity, 

 which promifed to Ieficn the wafte by diminifhing the va- 

 riety of operat'r-ns, and the length of the expofnre. Expe- 

 rience however has proved, that, in general, what was gained 

 hi weight was more than loll by the inferior quality of the 

 iron produced. 



With a view to produce a quality of iron from coak pig 

 equal or fuperior to what is obtained in the beft proceiTes 

 now in ufe, it occurred to me that an operation which would 

 unite the properties of the finery fire and of the puddling fur- 

 nace would be productive of a good quality of iron, and with 

 little comparative lofs. With this view a fmall furnace was 

 contrived, fomewhat fimilar in fhape to an iron-founder's 

 air furnace. The depth of the grates below what is called 

 the bridge of the furnace was more in proportion. A mal- 

 low cavity was formed in the middle of the furnace with 

 fand, about two inches deep, fifteen inches long, and eight 

 broad. The furnace was heated to a bright white heat with 

 raw pit-coal : a fmall door was then opened, and nearly 84 lbs. 

 of fragments of white crude iron introduced. The grates of 

 the furnace were then charged with coaks, and a femifufing 

 heat brought on, and continued for ten hours after. During 

 this operation the metal continued to boil, and difeharge a 

 blue vapour, frequently accompanied with hi fling explofions. 

 At lalt, when the metal exhibited no further figns of ebulli- 

 tion, rior of fufion, the fire was allowed to die away. When 

 cold, I found the whole, without ftirring or agitation, re- 

 folved into a mafs of malleable iron, which, even in this 

 tfate, was broken with great difficulty. The lump, or plate, 

 was divided into three pieces, one of which was drawn into 

 a {lout bar, and weighed 18 lbs. The quality of this iron 

 was excellent for every purpofe, flcel-making excepted. In 

 this procefs it disjoined, and formed laminae: which rendered 

 it unfit for any fteel purpofe. This experiment was fre- 

 quently 



