THE GAS COALS OF OHIO. 429 
the gas flame is produced by the incandescence of the carbon of the 
gas; still, as before stated, the best gas coals are those which contain 
the largest per cent. of hydrogen, and consequently smallest per cent. 
of carbon, and the less oxygen the better. 
The larger the per cent. of hydrogen that coal contains, the greater 
the quantity of carbon that can be volatilized, and the combustion of 
the hydrogen at the tip of the gas burner is necessary to produce the 
proper degree of temperature in the carbon to give us the incandescent 
light, and to eventually promote the ignition of carbon, and its con- 
version to carbonic acid, and thereby preventing the escape of free car- 
bon and the creation of smoke and deposition of soot. 
The analysis of the best gas coals often shows the per cent. of ash 
so great as to be almost beyond belief. The coke from Boghead 
cannel, a coal that yields 13,000 to 15,000 feet of thirty-five to forty 
candle power gas, has analyzed 70 per cent. of the weight of the coke 
in ash. Other good gas coals of the cannel character, range down to 
20 per cent. of the weight of its coke in ash. Coals used in gas-works 
of this and other countries vary in quality from one grade yielding 
6,000 feet to the net ton of thirteen candle gas, up to 12,500 feet of 131 
candle gas; the latter coal, if coal we are permitted to call it, being 
known as the Hartley mineral of New South Wales—the ene yielding | 
thirty-nine candle feet to the pound, the other yielding eight hundred 
and twenty-nine candle feet to the pound. 
The Albertite of Nova Scotia will yield 13,300 feet to the net ton 
of nearly fifty candle gas, or three hundred and thirty candle feet to the 
| pound. Grahamite, of West Virginia, 13,500 feet of twenty-eight 
candle gas, or one hundred and eighty-nine candle feet. 
But few persons can realize the magnitude of the gas industry of 
this country. There are-now in the United States more than seven 
hundred incorporated gas companies, doing business with a capital of 
over two hundred millions, and employing more than twenty-five 
thousand men. Just what amount of capital is employed in this State 
in the manufacture of and distribution of illuminating gas, could not 
be ascertained by the writer, but as more than ten per cent. of the total 
gas-works of the country are located in Ohio, it is probably not too high 
an estimate to place the capital at 73 per cent. of the total, or about 
fifteen million dollars, and this business has grown up almost entirely 
during the last generation. The first gas-works of the State were built 
