658 THE POPULAR SCIENCE MONTHLY. 



given to the American method the first decisive success in supplying 

 the public with water-gas. 



The oxygen of the steatai, as we have seen, on entering the burning 

 coals at the bottom of the furnace, instantly unites in full proportions 

 with the first carbon it encounters, forming carbonic acid. But this 

 carbonic acid, as fast as formed, is driven upward through the fire, 

 and, before it reaches the other gases, its greedy oxygen has gorged 

 itself with a double portion of carbon from the coals, and it is now 

 carbonic oxide — a gas rich with carbon, which is ready to unite in 

 combustion with a further proportion of oxygen wherever it can find 

 it. But it finds no oxygen among the gases to which it is introduced, 

 for the air-blast was shut off when the steam was let on. Consequent- 

 ly, it enters into the compound, and remains as a third combustible. 



Meanwhile, the mingled gases are rushing from the furnace, under 

 high pressure, through the flue into the secondary chamber or super- 

 heater, and up through the white-hot mass of fire-brick which it con- 

 tains. Struggling through the hot crevices in attenuated streams, the 

 gases reach a temperature of nearly 2,000°, at which all the elements 

 present are perfectly released and enabled to form such recombina- 

 tions as their stronger affinities dictate. As the oxygen here finds 

 itself in a hopeless minority, and remains dominated by the supera- 

 bundant carbon with which it is associated in carbonic oxide, there is 

 no rival to forbid the bans between the king and queen of combusti- 

 bles — Hydrogen and Carbon. 



The charge of coal in the generator makes from five to seven thou- 

 sand cubic feet of gas : the process of generation taking thirty minutes. 

 The steam is then shut off, and the generation of gas ceases. The lid 

 is raised, the air blast readmitted, and ordinary combustion is resumed. 

 The stoker approaches the fiery pit on a floor level with its mouth and 

 pours in another charge — a barrel of anthracite — fastens down the lid, 

 and for fifteen or twenty minutes the air-blast again urges combustion 

 until the mass in the generator is of a lively red, and the fire-bricks in 

 the superheater are once more white-hot for a second run of gas. At 

 every sixth charge the ashes are raked out, and two barrels of coal, 

 instead of one, are put on. 



When the eight sets of apparatus in the Baltimore works are in 

 operation, the actual product per twenty-four hours, with all delays, 

 amounts not unusually to 600,000 cubic feet ; and it has been practi- 

 cally demonstrated that 1,000,000 cubic feet could be made by the same 

 apparatus in the same time. Provision is also made for as many more 

 sets of apparatus as may be required by the future extension of the 

 business. 



We are now prepared to understand clearly the later and more 

 important process of making pure fuel-gSiB ; which commends itself to 

 us as the next great economic stride of the arts, and therefore as the 

 true " objective point " of this article. 



