WILLIAM SIEMENS, l-.R.S. 9! 



may rise naturally into the heating chamber, forming there a 

 plenum of pressure. 



Plates 13, 14, and 15 show the application of the regenerative gas 

 furnace as a round flint glass furnace. Plates 13 and 14 show 

 vertical sections of the furnace taken at right angles to each other, 

 and Plate 15 a sectional plan above and below the siege. The 

 round form of furnace is found convenient in flint glass-houses, 

 affording the greatest amount of accommodation to the glass- 

 blowers. The four regenerators C are here arranged below the siege 

 as before, and the air and gas from the hot regenerators enter the 

 annular heating chamber A at one side of the furnace, as shown 

 by the arrows in Fig. 10, and pass all round it, the products of 

 combustion escaping at the opposite side into the cold regenerators. 

 The direction of the current is reversed at intervals exactly as in 

 the plate glass furnace already described, by means of the re- 

 versing valves H and J in the air and gas passages, Figs. 11 and 

 12. Furnaces of this construction have lately been got to work at 

 Namur in Belgium and at Montlucon in France, and several 

 others of the same description are in course of erection at the 

 present time. The furnace just started by Messrs. Osier in 

 Birmingham also partakes of this form, being made semicircular. 



In setting out each individual furnace, the heating effect required, 

 the quality of the fuel employed, and the particular nature of the 

 process to be performed, have to be considered. The amount of 

 heat required determines the capacity of the regenerators ; and the 

 gas regenerators require fully as large a capacity as the re- 

 generators, and sometimes even a greater. This would perhaps 

 hardly be expected, but will be seen to be the case from the 

 following considerations. The gases proceeding from the gas 

 producers are a mixture of olefiant gas, marsh gas, vapour of tar, 

 water and ammoniacal compounds, hydrogen gas and carbonic 

 oxide ; besides nitrogen, carbonic acid, some sulphuretted 

 hydrogen, and some bisulphuret of carbon. The specific gravity 

 of this mixture averages 0'78, that of air being TOO ; and a ton 

 of fuel, not including the earthy remnants, produces according to 

 calculation nearly 64,000 cubic feet of gas. By heating these gases 

 to 8000 Fahr. their volume would be fully six times increased, but 

 in reality a much larger increase of volume ensues, in consequence 

 of some important chemical changes effected at the same time. 



