344 PROCEEDINGS OF THE AMERICAN ACADEMY 



is made by the combustion of other bodies present besides carbonic 

 oxide, but there are also sources of expenditure ; leaving as useful 

 etfect the amount of heat generated by ten pounds of iron burned, 

 from every one hundred pounds of melted iron taken. 



" I believe this combustion, going on momentarily with the reduc- 

 tion of the oxide, is sufficient to afford the excess of heat required to 

 maintain the temperature of the mass of iron above the initial temper- 

 ature for the short time of thirty or forty minutes, during which the 

 conversion takes place in a nearly closed vessel. 



" The other point in this connection is the condition of the pure 

 iron at the moment of its conversion. As this is most important 

 to a correct conception of the practical bearing of the method, it was 

 deemed necessary to describe briefly the ordinary mode of puddling 

 iron, and reference is now made to that part where it is stated, that, 

 as the iron becomes pure, it is less fusible. 



" In ordinary, this less fusible part is ' gathered,' and forms ' pud- 

 dle-balls ' ; if not thus removed, and time sufficient were allowed, the 

 whole charge would become consolidated, and could not be removed. 

 In the new method, the jets of air agitate or 'boil' the fluid iron, 

 and yet this solidification does not proceed, and it has been assumed 

 that the acting temperature is so high that the pure iron becomes 

 fluid. No evidence has been presented to sustain this assumption, 

 and it has been shown above, that there is no source of heat present 

 adequate to cause such fluidity. All the specimens of a suite illus- 

 trating the manufacture, prepared under the eye of Mr. Bessemer, 

 show that such heat of fluidity is unnecessary." (Dr. Hayes exhib- 

 ited these specimens, which illustrated, step by step, the conversion of 

 crude iron into pure iron, and the subsequent production of the inter- 

 woven particles forming wrought- iron, and the most finished speci- 

 mens of laminated sheets.) 



" These specimens prove that the molten mass of pure iron is not 

 a liquid iron, but a semi-fluid composed of crystals of pure iron, 

 which, in accordance with the laws of crystallization, have withdrawn 

 from the fluid, merely wet by the fluid iron present, and rendered 

 pultaceous by the carbonic oxide gas entangled. This physical con- 

 dition of the iron is represented by particles of hail mixed with a 

 small proportion of water, or more exactly by the mixture of crystals 

 of sugar and concentrated sirup, as it is filled into the forms ; such a 

 mass will flow and take sharp impressions in the moulds, while its 



