Mh. Cocket on Bessemer s Process for Manufacturing Malleable Iron. 8 1 



Merchant, 6 Hope Street ; Mr. Archd. Thomson, 3 Royal Terrace ; 

 Mr. Thomas Jackson, jun., Coats House, Coatbridge ; Mr. James 

 Robertson, L.R.C.S., Ed., Surgeon, Renfrew ; Mr. William Johnston, 

 6 Holland Place, St. Vincent Street. 



Mr. Cockey read a paper " On Bessemer's Process for Manufacturing 

 Malleable Iron." 



Bessemer s Process for Manufacturing Iron. By Me. William Cocket, 



This invention was first published to the world at the meeting of the 

 British Association, at Cheltenham, in 1856 ; and having excited a great 

 deal of attention, the makers of bar iron were generally anxious to 

 ascertain the value of the process. The experiment described in this 

 paper was performed at the Coates Iron Works, by Mr. Jackson. 



Seven and a-quarter hundredweight of No. 1 pig iron was put into 

 a founder's cupola, and when melted, was run off into a cylindrical fur- 

 nace of fire-brick, two feet deep, by about eighteen inches diameter, 

 previously heated, round the bottom of which there were six twyres 

 for delivering the blast from a blowing machine. The air was forced in 

 at a pressure of about eight pounds to the inch, afterwards increased to 

 ten pounds, and rising through the melted iron, a violent ebullition 

 commenced, and a red flame, from combustion of the carbon, issued from 

 the top of the furnace. In fifteen minutes fi-om the commencement of 

 the experiment, slag began to be vomited, and the combustion was very 

 vivid. In twenty minutes, most violent combustion was going on, and 

 slag was vomited forth in large quantities, accompanied by showers of 

 scintillating sparks, which were thrown to a distance of twenty or 

 thirty yards, surpassing in splendour the finest display of pyrotechnic 

 art. This violent commotion had nearly ceased in about thirty minutes 

 from the commencement, and ten minutes later the furnace was tapped, 

 and the purified iron run off. The exact weight was not ascertained, 

 but it was believed not to exceed three and a-half hundredweight, or 

 half the quantity of pig iron put into the cupola. 



When sufficiently cool, the Bessemer iron was taken to the rolling 

 mill, and rolled into a bar, which was cut and piled, again rolled, and 

 the piling and rolling once more repeated. The result was a bar of 

 crystalline iron, destitute of fibre, and, as was afterwards ascertained, 

 possessing very few of the properties of good malleable iron. 



The theory advanced by Mr. Bessemer was, that to convert cast iron 

 into malleable iron it was only necessary to deprive the former of its 

 carbon and other impurities, which he was able to effect by driving 

 atmospheric air through melted pig iron, in the manner here described ; 

 but it seems to be generally allowed, that although he was successful in 



Vol. IV.— No. 1. m 



