260 ANNUAL OF SCIENTIFIC DISCOVERY. 



the opening of the throat. When this is done he will run in his charge of 

 crude metal, and again commence the process. By the time the boil com- 

 mences the bar ends or other scrap will have acquired a white heat, and by 

 the time it is over most of them will have been melted and run down into the 

 charge. Any pieces, however, that remain may then be pushed in by the 

 workman, and by the time the process is completed they will all be melted, 

 and ultimately combined with the rest of the charge, so that all scrap iron, 

 whether cast or malleable, may thus be used up without any loss or expense. 

 As an example of the power that iron has of generating heat in this process, 

 I may mention a circumstance that occurred to me during my experiments. 

 I was trying how small a set of tuyeres could be used ; but the size chosen 

 proved to be too small, and after blowing into the metal for one hour and 

 three-quarters, I could not get up heat enough with them to bring on the 

 boil. The experiment was therefore discontinued, during which time two- 

 thirds of the metal solidified and the rest was run off. A larger set of tuyere 

 pipes were then put in, and a fresh charge of fluid iron run into the vessel, 

 which had the effect of entirely re-melting the former charge, and when the 

 whole was tapped out it exhibited as usual that intense and dazzling bright- 

 ness peculiar to the electric light. One of the most important facts connected 

 with the new system of manufacturing malleable iron is, that all the iron so 

 produced will be of that quality known as charcoal iron ; not that any char- 

 coal is used in its manufacture, but because the whole of the processes follow- 

 ing the smelting of it are conducted entirely without contact with, or the use 

 of any mineral fuel; the iron resulting therefrom will, in consequence, be 

 perfectly free from those injurious properties which that description of fuel 

 never fails to impart to iron that is brought under its influence. At the same 

 time, this system of manufacturing malleable iron offers extraordinary facility 

 for making large shafts, cranks, and other heavy masses ; it will be obvious 

 that any weight of metal that can be founded in ordinary cast iron by the 

 means at present at our disposal, may also be founded in molten malleable 

 iron, and be wrought into the forms and shapes required, provided we in- 

 crease the size and power of our machinery to the extent necessary to deal 

 with such large masses of metal. A few minutes' reflection will show the 

 great anomaly presented by the scale on which the consecutive processes of 

 iron making are at present carried on. The little furnaces originally used 

 for smelting ore have, from time to time, increased in size, until they have 

 assumed colossal proportions, and are made to operate on 200 or 300 tons of 

 materials at a time, giving out ten tons of fluid metal at a single run. The 

 manufacturer has thus gone on increasing the size of his smelting furnaces, 

 and adapting to their use the blast apparatus of the requisite proportions, and 

 has, by this means, lessened the cost of production in every way ; his large 

 furnaces require a great deal less labor to produce a given weight of iron 

 than would have been required to produce it with a dozen furnaces; and in 

 like manner he diminishes the cost of fuel blast and repairs, while he insures 

 a uniformity in the result that never could have been arrived at by the use 

 of a multiplicitj- of small furnaces. AVhile the manufacturer has shown him- 

 self fully alive to these advantages, he has still been under the necessity of 



