SfK WILLIAM SIEMENS, F.R.S. 97 



in the drainage of the premises. No permanent difficulty could 

 be anticipated in carrying out the new puddling furnace in 

 practice, on account of the large amount of experience gained in 

 the application of the regenerative furnace for other purposes. 

 There was only one chimney to a number of furnaces, and the 

 draught was simply regulated by a separate damper to each 

 furnace. The chimney was not required to be lined with fire- 

 brick, but was built of red bricks, as the heat passed off from 

 the puddling chamber was all arrested in the regenerators and 

 the chimney was always cool. The chimney damper regulated 

 only the force of draught in each furnace, but the quantity and 

 quality of flame were regulated by the gas valve. No furring- 

 up had taken place in the regenerators, because the steam mixed 

 with the gas would volatilise any carbon that might otherwise 

 be deposited on the walls of the regenerator : it was for this 

 purpose that care was taken to supply an excess of vapour of 

 water from the water trough in the grate of the gas producer 

 A regenerative heating furnace had been three years in constant 

 work at Messrs. Marriott and Atkinson's Steel Works, Sheffield, 

 heating" the steel for the rolling mill, and no inconvenience had 

 been experienced from vitrification of the materials of the fur- 

 nace. Mr. Atkinson was prevented from being present at the 

 meeting himself as he had wished, but had sent "a letter ex- 

 pressing his satisfaction with the furnace, as especially advan- 

 tageous for heating steel on account of the uniformity of the 

 heat obtained in it. The glass-melting furnace at Messrs. Lloyd 

 and Summerfield's had also been in constant work for nearly a 

 year without sustaining any injury from the great heat employed 

 in it. The temperature in the furnace was at least a full welding 

 heat of iron, as a bar of iron held in it dropped melted in half 

 a minute ; the hot end of the regenerator had a temperature of 

 about 3000 Fahr., and the heat in the furnace must of course be 

 greater. For measuring such high temperatures he made use of the 

 pyrometer described at a previous meeting,* consisting of a well 

 protected vessel containing a measured quantity of water, and a piece 

 of copper or platinum of definite size, which was exposed for a suffi- 

 cient length of time to the heat to be measured and was then dropped 



* See Proceedings of the Institution of Mechanical Engineers, 1860, p. 59. 

 VOL. I. H 



