

WILLIAM SIEMENS, F.R.S. 95 



inferior fuel abounds. This applies most forcibly to the South 

 Staffordshire district, where the best coal in lumps is worth 12s. Gd. 

 per ton, whereas good slack can be had at 3s. or 4s. per ton. The 

 question gains moreover in importance when it is considered that, 

 according to the best authorities, the thick coal of the district is 

 coming to an end, while millions of tons of coal-dust have accu- 

 mulated, of no present commercial value, which on being converted 

 into gas in the manner described by means of the gas producers 

 would acquire a heating value equal at any rate to the same weight 

 of the best coal in the manner in which it is at present used. 

 Considering also the proximity of the pits to the ironworks in this 

 district, it may be suggested whether the gas producers being of 

 very simple construction might not with advantage be placed near 

 the banks of fuel above or even under ground, the gas being con- 

 veyed to the works by a culvert so as to supersede carting of the 

 fuel. Such an arrangement might notably contribute to per- 

 petuate the high position which South Staffordshire has so long 

 maintained as an iron producing district. 



In the discussion of the Paper 



MR. SIEMENS observed that the essential features of the regene- 

 rative gas furnace described in the paper, as now matured and 

 carried out in practice, were the separate gas producers, in which the 

 solid fuel was converted into a gaseous form for use in the furnace, 

 and the regenerators, in which the gas and air were each raised to 

 a high degree of temperature previous to their mixture and com- 

 bustion in the furnace, whereby the heat produced by the combus- 

 tion was very greatly increased. In the gas producers the fuel 

 underwent a slow digestion, and the whole of the combustible 

 constituents were drawn off into the furnace in the form of gas. 

 while the incombustible ash or valueless portion of the fuel was 

 left behind. The gas produced was of a crude nature in its 

 original state, and much inferior to common gas for illuminating 

 or heating purposes, and if burnt only with ordinary air would 

 give very poor results : but it underwent a further change in the 

 regenerator where it was heated up to about 3000 Fahr., at 

 which temperature the several gaseous compounds contained in it 

 became decomposed, the rich carburetted hydrogen depositing 



