696 CREATIVE CHEMISTRY restricted in their operation, while large containers of coal gas carried on the roofs of vehicles, cylinders of compressed gases, and special carbonizers built onto cars to produce fuel gases by burning wood and other fuels have been introduced. In 1940 the investments in the petroleum industry amounted to $14,500,000,000. In 1939 the "billion-dollar breathless moment," i.e., the day of the year when the nation's gasoline-tax bill passed the billion-dollar mark, fell on December 15, while in 1940 it arrived on November 15. The petroleum industry has thus helped to build the national wealth through taxes, which, in 1939, totaled more than four times the net earnings of the industry. The value of the products of the petroleum industry in 1939 was $2,461,126,549, according to the United States Department of Commerce. The Petroleum Resources of the United States Will Not Soon Be Exhausted. The crude-oil reserves in known oil fields are about 20,000,000,000 barrels, or sufficient to last sixteen years at the present rate of consumption. Improved methods of oil-well operation, such as gas injection, air injection, acidizing (treating with hydrochloric acid), and flooding with water, have brought about startling increases in oil recovery from old fields in recent years. Modern drilling methods have eliminated the loss due to gushers. The Petroleum Industry Is the Second Largest in Its Research. Employment of Slowly, but surely, the method of Science will help to make life more intelligent, toil more cheerful, fear and hatred and tears less abundant for mankind. — A. J. Carlson.^ In 1938 the petroleum industry employed over 5000 research workers, while more than $20,000,000 was spent in petroleum research in 1939. Through research, refining processes have become more efficient. Only about half as much fuel is consumed today as w^as consumed in 1925 in the refining of a barrel of oil, while twice the amount of gasoline refined for a given investment in 1925 is now produced for the same investment. Production operations have also been made more efficient. Under older methods only about 20 per cent of the oil present in producing formations could be brought to the surface, while modern methods have nearly tripled this yield. • Science News Letter, January 11, 1941, p. 29.
"BETTER THINGS" FROM PETROLEUM 697 Research has decreased the cost of gasoHne. The average servicestation price of gasoHne in 1920, minus taxes, was 29.7 cents per gallon, while it had been reduced to 13.4 cents per gallon by 1939. Modem Petroleum-prospecting Is Scientific. During the 17 years starting with 1922, 1183 new oil fields were discovered, 796 of which were major pools estimated at more than 1,000,000 barrels of recoverable oil each. Of these 796 major pools, 746 were discovered by geological and geophysical methods, thus leaving only 50 pools to the credit of random drilling or "wildcatting." The newer tools of geophysics include seismography, the torsion balance, the gravitometer, the magnetometer, and the electric log. Geochemical methods, by which samples of soil are analyzed for waxes, oil, and hydrocarbon gases and which are so sensitive that a few parts of ethane per billion may be determined, are now coming into vogue. The mass-spectrograph of the physics laboratory is the modern geochemical divining rod. Analyses may be made on samples of gases smaller In volume than the head of a pin, and the results may be obtained within ten minutes. Seismographic exploration uses sound waves from test explosions sent down through one stratum after another and recorded as they bounce back. From these data underground configurations are plotted and the possibility of oil-bearing structures determined. Another modern device is an electric eye which is very sensitive to gamma rays. It is lowered into a well, where it responds to varying emissions of gamma rays from different strata, thus helping to identify them. Twenty years ago wells cost about $10,000 each and went down only 2000 to 3000 feet. Now wells may cost $150,000 or more and frequently are drilled to a depth of from 8000 to 15,000 feet. Many Improvements Have Been Made in the Manufacture of Motor Fuels and Lubricants. About half of the gasoline produced today comes from the cracking of petroleum. This gasoline possesses antiknock properties, so that the octane number * of the average gasoline not treated with tetra- 1 Octane number — In the standard method for rating the antiknock value of gasoline, iso-octane, CH3 CHs CHs—CH—CHi—C—CH3 CHa is arbitrarily assigned the value of 100, while normal heptane, CH3— CH2 — CH2 — CH2 — CH2—CH2—CH3, is given the value of 0. The percentage of iso-octane that has to be mixed with heptane to reduce the intensity of the knocking of the mixture to that of the gasoline is called the antiknock rating or, preferably, the octane number.