tion and on the nature of the products. The experiments show that the oxidation of coal goes on appreciably at ordinary temperatures and increases with great rapidity as the temperature rises. Different coals vary widely in rate of oxidation, showing a relationship in this respect which is parallel to that of their relative inflammability in the form of dust. The oxidation reaction is, at the lower temperatures, largely an addition of oxygen to the coal substance, although water, carbon dioxide, and even carbon monoxide, begin to be formed at temperatures slightly above the ordinary. Below 250° C. water is the chief product of the oxidation of most coals.

The destructive distillation of coal, or its decomposition by heat, is being studied in somewhat similar manner, the fundamental reactions involved and primary products formed at different temperatures being determined. It has been shown that the primary decomposition products of the better grades of coal are largely made up of hydrocarbons of the methane type, whereas those of other coals contain relatively large quantities of water, carbon dioxide, and carbon monoxide. Whether coal is heated at high or low temperatures, rapidly or slowly, the primary products are much the same, the secondary reactions producing, however, different final products. The importance of these studies lies in the fact that the two processes of oxidation and of destructive distillation are fundamental in all methods of utilizing coal and in its accidental combustion, as in explosions of coal dust in mines.

These investigations were in charge of Horace C. Porter, chemist, assisted by O. C. Ralston, G. B. Taylor, and F. B. Furber, junior chemists.

INVESTIGATION OF THE SOLUBLE CONSTITUENTS OF COAL.

One of the methods the chemist can use in studying the constituents of coal consists in separating the soluble constituents by various solvents, chiefly organic, and then further separating the dissolved substance by means of fractional solution.

In continuance of the work of the fiscal year 1912, the investigation of the past fiscal year has had to do with the pyridine extract of bituminous coal from the Pittsburgh bed. A fraction of this extract, soluble in methyl alcohol, has been studied in considerable detail. From the methyl alcohol extract, by means of fractional distillation under diminished pressure, nine separate fractions have been obtained. Further examination of these fractions is required before the significance of the results thus far obtained can be definitely stated.

Other fractions of the pyridine extract, already separated by means of ether and petroleum ether, will be examined later in a similar way.

A review of the literature on the constitution of coal and the preparation of a bibliography and historical résumé of the results obtained up to the present time by the method of extraction have received attention.

The investigation described was in charge of E. J. Hoffman, assistant chemist.

PETROLEUM TECHNOLOGY.

FIELD INVESTIGATIONS.

The bureau's investigations relating to the efficient production and utilization of petroleum and petroleum products include the study of well-drilling methods, with especial reference to the prevention of waste of oil and gas at wells on or adjacent to public lands; the study of methods of storing and transporting oil and natural gas with a view to lessening loss in transit and in storage; the study of means for decreasing fires from lightning, which have caused heavy losses in the southern and middle western States; the study of refining methods in order to ascertain the best process of refining petroleum and improving the quality and increasing the yield of commercial products; and the study of fuel oils belonging to or intended for the Government, with especial reference to increasing efficiency and economy in their utilization.

Investigations of methods of drilling wells, and the various types of drilling rigs, tools, and appliances were continued in California, Oklahoma, Louisiana, Colorado and Wyoming, and in other States. Methods used in the Oklahoma oil fields were studied in detail, and samples of oil were obtained from all the producing fields of the State.

WASTE OF OIL AND GAS IN CALIFORNIA.

In November, 1912, Ralph Arnold, petroleum engineer, visited the California oil fields in company with J. A. Pollard, consulting engineer, with the object of investigating methods of preventing the waste of oil and natural gas from flowing wells. Especial attention was given to the capping of gushers and gassers in the "gusher territory" of the Midway-Sunset fields. In December Mr. Arnold conducted a similar investigation in company with Mr. A. C. Mortenson, and in January made an extended trip in company with W. R. Calvert, consulting geologist, to investigate the prevention of waste and the most efficient methods of utilizing oil and gas in connection with "topping" and natural-gas gasoline plants.

The results of some of these investigations were published in a technical paper, and a description of the cementing process of excluding water from oil wells as practiced in California was published as another technical paper.

In the latter part of the fiscal year a study of the different methods used at oil wells in California for recovering oil was made, and the results were prepared for publication.

WASTE OF OIL AND NATURAL GAS IN THE MID-CONTINENT FIELD.

The bureau has made a careful examination of the conditions attending the development of oil and gas pools in Oklahoma, many of which are in Indian lands, in the endeavor to ascertain the wastes of oil and gas under the existing methods of drilling wells and of transporting and utilizing gas and oil, and to discover means whereby such waste could be prevented without hardship to the operator and to the advantage of the public.

To ascertain the conditions that have led to enormous waste of natural gas in Kansas and Oklahoma, L. S. Blatchley, consulting geologist, visited the principal oil pools in those States. He found that not only had little effort been made to save gas (casing-head and flow-tank gas) at many oil wells, but that gas wells had been allowed to blow into the air daily millions of cubic feet of this ideal natural fuel. He also found that there had been great waste in the utilization of gas, chiefly through using it for purposes for which it should not be used, or selling it at prices that discouraged economy in its use. Mr. Blatchley also found that there had been much waste of petroleum in the form of sludge and residue from oil tanks. His findings are being prepared for publication as a technical paper.

As a result of its investigations in California and Oklahoma the bureau ascertained the feasibility of drilling oil wells in Oklahoma by means of cable tools and the use of mud-laden water to seal the sides of the wells, and thus prevent the escape of gas from sands overlying the oil sand. Having ascertained the practicability of the method, the bureau had one of its petroleum engineers, J. A. Pollard, demonstrate the ease with which wells could be drilled and waste of oil and gas prevented when the method was used. Already the waste of millions of feet of gas has been stopped and the life of the Cushing gas field has been prolonged. Further work should demonstrate the industrial value of the gas in this field, and pipe-line connections may then be made to transport the gas to a market.

Already the methods introduced in the Cushing field are being used in the field near Okmulgee, Okla. These methods not only save gas, prevent water from entering gas or oil sands, and decrease the liability of disastrous fires, but enable some wells to be completed at less cost than by the methods hitherto used in that State.

OIL AND GAS WELLS THROUGH WORKABLE COAL BEDS.

An investigation was conducted to ascertain the dangers to miners from natural gas escaping into mines through improperly drilled or

imperfectly plugged oil or gas wells, the waste of gas from improper methods of bringing in and casing wells, and to suggest regulations that might be adopted by State legislatures to prevent waste of resources and protect miners.

Wells in Pennsylvania, Ohio, and West Virginia were visited and conferences were held with coal operators, gas and oil well operators, State geologists, separately and jointly. The dangers to life and property were analyzed in the light of experience and provisions to reduce the hazards were suggested. The results of the investigation and the regulations proposed were published in a bulletin and in a technical paper.

This investigation was in charge of G. S. Rice, chief mining engineer, and O. P. Hood, chief mechanical engineer, aided by L. M. Jones, engineer, and A. G. Heggem, petroleum engineer.

OTHER INVESTIGATIONS.

A report dealing with wastes in the production and utilization of natural gas in the United States, calling attention to the principal ways in which gas has been wasted and the means to be taken for preventing these wastes, which was written by F. G. Clapp and Ralph Arnold, petroleum engineers, was published as a technical paper.

A report on the possible causes of the decline of oil wells, as governed by the relations of oil, salt water, and gas in porous strata, and the movement of oil underground and some suggested ways of prolonging the yield of wells by drilling with reference to such conditions as can be determined by cooperation among the owners of adjoining leases was prepared by L. G. Huntley and submitted for publication.

The occurrence of oil and gas in Wyoming, the conditions governing the development of the oil and gas fields in the State, and the waste that has taken place in their development were investigated by W. R. Calvert, consulting geologist.

LABORATORY INVESTIGATIONS.

EXAMINATION OF PETROLEUM AND PETROLEUM PRODUCTS.

The petroleum laboratories of the bureau studied methods of increasing efficiency and safety in the utilization of petroleum and its products for fuel and for other purposes, and analyzed and tested samples of oil collected in different fields.

One of the most important tasks undertaken during the year was a study of better methods of refining crude oil. This is being done in collaboration with the producers and the refiners of crude oil and the users of petroleum products. The work is being materially aided

by members and committees from the following scientific societies: American Chemical Society, American Society for Testing Materials, International Society for Testing Materials, International Petroleum Commission, National Petroleum Association, Western Petroleum Refiners' Association, National Fire Protection Association, Independent Agencies of California and Texas, Independent Petroleum Marketers' Association, Bureau for the Safe Transportation of Explosives and Other Dangerous Articles, also by professors of chemistry and engineering in several universities in the United States and by a number of commercial-testing laboratories. As a result a national society for the study of petroleum and its products is being formed.

A large number of analyses were made for the Army, Navy, and Post Office Departments, the Office of the Supervising Architect, and for other Government bureaus.

Aside from these, many analyses were made in the study of crude oils from the California, Louisiana, and other fields. In all, about 4,700 individual tests were made during the year.

The laboratory investigations of petroleum are centered in the experiment station in Pittsburgh and are in charge of Irving C. Allen, petroleum chemist, who is assisted by W. A. Jacobs and A. S. Crossfield, junior petroleum chemists.

CHEMICAL INVESTIGATIONS OF NATURAL GAS.

With the object of devising methods whereby natural gas can be utilized with greater efficiency, chemical investigations of the natural gas found in the United States were continued at the Pittsburgh station. In connection with this work, 146 samples of natural gas, from almost every State in which natural gas is found, were analyzed. The samples included methane or marsh-gas from fields that produce no petroleum, natural gas from oil fields, and also casing-head gas and flow-tank gas from oil wells.

As part of an investigation of the suitability of different classes of natural gas for the production of gasoline, samples of raw gas, of gasoline obtained by compression, and of the residual gas left after compression were collected at plants making gasoline from natural gas, 25 such plants in Oklahoma alone being visited. A special study was made of the technical methods used in this industry, and a bulletin on the subject is being prepared.

By methods developed in the laboratory at Pittsburgh the separation of Pittsburgh natural gas into its constituent individual hydrocarbon compounds was successfully accomplished, a step that will greatly facilitate the determination of the industrial value of various grades of natural gas. The method used comprised liquifaction and fractional distillation,