PETROLEUM. 155 







character of the oil, the yield of illuminating oil can be increased, but 

 a residuum is always left in the large stills to be afterward treated in 

 smaller ones. 



S. D. Hayes states that this operation can be reversed, and from 

 two to ten per cent, of a heavy oil obtained from the lightest and 

 cheapest gasolene or petroleum naphtha. This change he observed 

 in an apparatus constructed by Mr. Z. A. Willard, for generating 

 gases and hydrocarbon vapors for metallurgical purposes. It consisted 

 essentially of upright wrought-iron cylinders, half-full of the naphtha, 

 through which steam at the ordinary working temperature and press- 

 ure passed, vaporizing the naphtha, and maintaining a pressure of about 

 fifty pounds to the inch. The steam and naphtha vapors were thus 

 kept above the liquid at a temperature much above the boiling-point 

 of naphtha, but never as high as 300 Fahr., and the decompositions 

 appeared to occur rather in the vapors than in the liquid. The heavy 

 oil drawn off below had a dark yellowish-brown color, was nearly 

 odorless after a few days' exposure to the air, had a specific gravity 

 of about 34 Beaume, and boiled above 400 Fahr. By redistilling, it 

 was broken up into lighter and heavier liquid hydrocarbons, paraffine, 

 and separated carbon [American Journal of Science, III., ii., 184). 



Petroleum as a Fuel and Gas-Producer. The use of gasolene in 

 gas-machines is well known, and sometimes naphtha has been used to 

 enrich coal-gas, by decomposing its vapor at a cherry -red heat, so as 

 to produce a gas rich in heavy hydrocarbons, which is mixed with 

 the coal-gas. Crude petroleum has also been conducted continuously 

 into red-hot cast-iron retorts, whereby it is decomposed and rich gas 

 formed. The Lowe process, now making daily 120,000 cubic feet of 

 gas, of 19.5 candle-power, for a five-foot burner, at Utica, New York, 

 is very successful. It consists essentially in forcing steam through a 

 generator partly full of anthracite coal, brought to intense ignition ; 

 the steam is decomposed, and the resulting hydrogen meets crude pe- 

 troleum that trickles down through the top of the generator; the 

 petroleum is carried in vapor with the hydrogen into a " superheater " 

 filled with loose fire-bricks, previously intensely heated by the gases 

 from the generator. Here the hydrogen and hydrocarbons react upon 

 each other, producing a permanent gas, which is purified as usual. 

 The resulting gas is of uniform quality, very pure, and the saving in 

 labor and materials is about 35 per cent, over coal-gas {Scientific 

 American, January 8, 1876). 



As regards the use of petroleum for fuel, it has always been found 

 difficult to secure the complete combustion of the oil, so as to avoid 

 smoke ; the complicated nature of the contrivances devised for its use 

 has also worked against its introduction as a fuel ; but a furnace for 

 reheating and rolling scrap-iron into boiler-plate has been invented 

 by C. J. Eames, and is worked in Jersey City, which deserves men- 

 tion. Prof. H. Wurtz (American Chemist, September, 1875) has de- 



