252 THE SCIENTIFIC PAPERS OF 



larly by the ordinary puddlers of the works, and that no repairs 

 have been necessary to the gas puddling furnace since November 

 last, the roof being reported to be still in excellent condition. 



In these investigations I have confined myself to the puddling 

 of ordinary English forge pig in order to avoid confusion, but it 

 is self-evident that the same reasoning also applies in a modified 

 degree to white pig metal or refined metal, the use of which I 

 should not, however, advocate. 



WATER BRIDGES. Regarding the water bridges, I was desirous to 

 ascertain the expenditure of heat at which the saving of "fettling" 

 and greater ease of working was effected. The water passing 

 through the bridges was accordingly measured by Mr. W. Hackney 

 (who has also furnished me with the other working data) and found 

 to amount to 25 Ibs. per minute, heated 40 Fahr. This represents 

 60,000 units of heat per hour, or a consumption not exceeding 8 Ibs. 

 to 10 Ibs. of solid fuel per hour, an expenditure very much exceeded 

 by the advantages obtained where water or cooling cisterns are 

 available. 



The labour of the puddler and of his underhand being very much 

 shortened and facilitated by means of the furnace, I should strongly 

 recommend the introduction of three working shifts of 8 hours each 

 per 24 hours, each shift representing the usual number of heats, by 

 which arrangement both the employer and the employed would be 

 materially benefited. The labour of the puddler may be further 

 reduced with advantage by the introduction of the mechanical 

 " Rabble " which has already made considerable progress on the 

 Continent. 



By working in this manner, a regenerative gas puddling furnace 

 of ordinary dimensions would produce an annual yield of about 940 

 tons of bar iron, of superior quality, from the same weight of grey 

 pig metal and the ordinary proportion of " fettling." 



In conclusion, I may state that a considerable number of these 

 puddling furnaces have been erected by me abroad, and that, in 

 this country, they are also being taken up by the Monkbridge 

 Iron Co., Leeds, and a few other enterprising firms. 



The construction of these furnaces has been still further improved 

 lately by the application of horizontal regenerators, to save deep 

 excavations, and by other arrangements whereby the first cost is 

 diminished and the working of the furnace facilitated. 



