244 



THE SCIENTIFIC PAPERS OP 



impurities thus taken up will mainly depend upon the temperature, 

 which should be high, in order to ensure the perfect fluidity and 

 complete separation of the cinder. 



The following was the result of an analysis of an inferior English 

 pig iron before and after being puddled : 



PIG METAL. 



Sulphur 



Phosphorus . . . 

 Silicon 



Iron and Carbon (by 

 difference) . . . 



08 

 1-16 

 1'97 



96-79 

 100-00 



PUDDLED BAB. 



Sulphur 



Phosphorus . 



Silicon 



Iron (by difference) 



017 



237 



200 



99-546 



100-000 



showing the extent to which foreign matters are actually removed 

 by the process of puddling. 



These analyses were made a few days since by Mr. A. Willis in 

 my laboratory at Birmingham. 



Led by these chemical considerations, and by practical attention 

 to the subject, extending over several years, I am brought to the 

 conclusion that Ihe process of puddling, as practised at present, is 

 extreme!// "wasteful in iron and fuel, immensely laborious, and 

 .yielding a metal only imperfectly separated from its impurities.^ 



How nearly we shall be able to approach the results indicated 

 by the chemical reasoning here adopted, I am not prepared to say, 

 but that much can be accomplished by the means actually at our 

 doors is proved by the result of the working of a puddling fur- 

 nace erected eighteen months since to my designs by the Bolton 

 Steel and Iron Company in Lancashire. 



This furnace consists of a puddling chamber of very nearly the 

 ordinary form, which is heated however by means of a regenerative 

 gas furnace, a system of which the principle is now sufficiently 

 well established to render a very detailed description here un- 

 necessary. 



The general arrangement of the furnace is shown in the accom- 

 panying illustrations. It consists of two essential parts : 



The gas-producer, in which the coal or other fuel is converted 

 into a combustible gas ; and 



The furnace, with its " regenerators " or chambers for storing 



