SIR WILLIAM SIEMENS, F.R.S. I I I 



the grate in a pool, into which the hot clinkers falling generate 

 steam, which must be delivered in the proportion of at least 

 007 Ib. per pound of fuel, or 6 Ibs. per ton. It is therefore 

 evident that the loss of heat caused in converting the fuel to the 

 gaseous condition amounts only to 12 J per cent, of the total 

 quantity in the fuel, and this even is turned to useful account by 

 causing an onward pressure towards the furnace, in the passage 

 of the gas through the cooling syphon, thus avoiding the necessity 

 of an artificial blowing apparatus and a closed grate, which would 

 be sources of considerable inconvenience in practice. 



Against this small theoretical loss must be set the advantages 

 of perfect combustion in the furnace, into which gas and air are 

 admitted through valves in proper proportions, and the further 

 main advantage resulting from the application of the regenerators, 

 which I need not here particularise. 



The unfavourable estimate which Mr. Bell has formed of the 

 working condition of the gas producer has betrayed him into 

 under-estimating the practical saving realised by the adoption of 

 the regenerative gas-furnace. The amount of this saving depends 

 in a great measure upon the temperature at which the work in the 

 furnace is being accomplished, the economy increasing with the 

 degree of that temperature. Thus in melting mild steel in cru- 

 cibles, an operation requiring intense heat, about 3 tons of Durham 

 coke are required in the old process per ton of steel melted, which 

 work is accomplished in the regenerative gas furnace with a con- 

 sumption not exceeding 25 cwt. of ordinary coal. In carrying 

 out such operations as the melting of glass and the reheating and 

 puddling of iron great saving has also been effected, but one of 

 the largest applications of the system has been made to the 

 reheating of Bessemer steel, requiring, as is well known, less 

 intense heat than is required for the heating of glass and iron, and 

 with reference to this application I cannot do better than quote 

 Mr. J. J. Smith's paper, read before the Iron and Steel Institute 

 on the 22nd September, 1869, in which he says, "The results at 

 the Barrow Works, taken over a period of two years, show 44 per 

 cent, (saving), but the comparison is taken with furnaces built 

 expressly to consume the hardest and best coal which could be 

 procured, and notwithstanding the known loss previously men- 

 tioned in forcing the producers ; but as the quality of the coal 



