g6 THE SCIENTIFIC PAPERS OF 



carbon which was at once taken up by the vapour of water present, 

 producing carbonic oxide and hydrogen ; so that there was then 

 present the greatest amount of free hydrogen, which had three or 

 four times the heating power of any other gas. The air used for 

 burning the gas was also heated by the regenerator up to about 

 3000 and then mixed with the gas at the same temperature, 

 producing perfect and most intense combustion : the regenerative 

 system thus presented the means of attaining an almost unlimited 

 degree of temperature. At the same time there was no great 

 current or draught through the furnace, since the chimney draught 

 was not required in this furnace to urge the combustion as in 

 ordinary furnaces heated by solid fuel, and the cutting draughts 

 destructive of ordinary furnaces were therefore entirely avoided. 

 There was no difficulty in keeping up an abundant supply of gas 

 if there were enough gas-producers and if the passages to the 

 furnace were large enough ; the puddling chamber could then be 

 completely filled with flame at any moment, or the flame could be 

 as instantly stopped, by means of the regulating valves and 

 chimney damper. By having separate air and gas valves the 

 chemical nature or heating power of the flame could also be 

 regulated to any desired degree, by altering the proportion of air 

 admitted with the gas, so as to produce any required effect from a 

 smoky flame to a pure bright flame. In the furnace for flattening 

 the cylinders of sheet glass a quantity of bright clean flame was 

 required for softening the glass without melting it ; but in the 

 melting furnace, on the contrary, an intense soaking heat was 

 wanted, with very little variation : and both sorts of heat were 

 obtained in the new furnace from the same gas main, by simply 

 regulating the quantities of air and gas admitted. Of the 

 puddling furnaces two were now just being started in the South 

 Staffordshire district, but about twenty puddling and heating 

 furnaces had been at work in Germany for some months already 

 with complete success. They had not yet obtained any absolute 

 results with the regenerative puddling furnaces in this country, 

 but at present the time of working a heat was about the same 

 as in the ordinary puddling furnaces. The puddling furnaces 

 working on this plan near Wolverhampton were not yet in a 

 complete state for operation as they had been expected to be 

 before this time, on account of a defect in the chimney flue and 



