1862.] on Gas-FurnaceSf ^c. 539 



goods, being put in and taken out at the same end, those which 

 enter last and are withdrawn first, remain, of course, for a sliorter time 

 in the heat at that end ; and though the fuel and air enters first at one 

 end and then at the other, alternately, still the necessary difference of tem- 

 perature is preserved by the adjustment of the apertures at those ends. 



Not merely can the supply of gas and air to the furnace be go- 

 verned by valves in the passages, but the very manufacture of the 

 gas fuel itself can be diminished, or even stopped, by cutting off the 

 supply of air to the grate of the gas-producer; and this is important, 

 inasmuch as there is no gasometer to receive and preserve the aeriform 

 fuel, for it proceeds at once to the furnaces. 



Some of the furnaces have their contents open to the fuel and com- 

 bustion, as in the puddling and metal-melting arrangements; others are 

 enclosed, as in the muffle furnaces and the flint-glass furnaces. Because 

 of the great cleanliness of the fuel, some of the glass furnaces, which 

 before had closed pots, now have them open, with great advantage to 

 the working and no detriment to the colour. 



The economy in the fuel is esteemed practically as one-half, even 

 when the same kind of coal is used either directly for the furnace or 

 for the gas-producer ; but, as in the latter case, the most worthless 

 kind can be employed — such as slack, &c., which can be converted 

 into a clean gaseous fuel at a distance from the place of the furnace, 

 so, many advantages seem to present themselves in this part of the 

 arrangement. 



It will be seen that the system depends, in a great measure, upon 

 the intermediate production of carbonic oxide from coal, instead of the 

 direct production of carbonic acid. Now, carbonic oxide is poisonous, 

 and, indeed, both these gases are very deleterious. Carbonic acid 

 must at last go into the atmosphere ; but the carbonic oxide ceases to 

 exist at the furnace, its time is short, and whilst existing it is confined 

 on its way from the gas-producer to the furnace, where it becomes 

 carbonic acid. No signs of harm from it have occurred, although its 

 application has been made in thirty furnaces or more. 



The following are some numbers that were used to convey general 

 impressions to the audience. Carbon burnt perfectly into carbonic 

 acid in a gas-producer would evolve about 4000° of heat ; but, if burnt 

 into carbonic oxide, it would evolve only 1200°. The carbonic oxide, 

 in its fuel form, carries on with it the 2800° in chemical force, which 

 it evolves when burning in the real furnace with a sufficient supply of 

 air. The remaining 1200° are employed in the gas-producer in dis- 

 tilling hydro-carbons, decomposing water, &c. The whole mixed 

 gaseous fuel can evolve about 4000° in the furnace, to which the 

 regenerator can return about 3000' more. 



[M. F.] 



