The New International Encyclopædia/Petroleum

​PETROLEUM (ML., rock oil). A natural rock oil composed of hydrocarbons. It is classed with natural gas and asphalt as a bitumen;natural gas containing the more volatile members of the series, asphalt the solid, while petroleum is composed chiefly of the liquid members, although it contains a small proportion of both solid and gaseous compounds. Other names for petroleum are mineral oil, rock oil, and naphtha, the last being employed especially in Europe for theRussian oils.

History. Petroleum has long been known in various parts of the world by its appearance in the form of bituminous springs or as a floating scum on the surface of pools. It was used at a very early period in the walls of Babylon and ​Nineveh, and Herodotus has described the occurrenceof oil springs in the island of Zachynthus, now Zante. In Roman times petroleum was obtained from Sicily and burned in lamps. The firstmention of petroleum in America (about 1635) is in a letter written by the Franciscan missionaryJoseph de la Roche d'Allion, who refers therein to springs found in the region of what is nowsouthwestern New York or northwestern Pennsylvania. The early settlers of Pennsylvania obtained smallquantities of oil by digging wells and scooping out the liquid which seeped in from the surroundingrocks. The drilling of brine wells on the western slopes of the Alleghanies in the earlypart of the nineteenth century led to the discovery of petroleum at greater depths. A well sunk near Burkesville, Ky., in 1829, yielded greatquantities of oil, which flowed to the surface and was drained into the Cumberland River, where at one time it was set on fire. The most importantapplication of petroleum in the early days was in medicine; it was utilized as an illuminant only to a small extent, owing to its offensive odor. In the year 1853 Dr. Brewer suggested the use ofpetroleum for lubricating and illuminationpurposes, and set to work devising means for purifyingthe crude product. The Pennsylvania Rock-OilCompany was organized in 1854 to drill for oil; although its first well yielded from 400 to 1000 gallons a day, the company was not successfulin its business ventures. Five years later, however, Col. E. L. Drake put down a productive well on land leased from this company, and the successful outcome of this undertaking may be said to mark the beginning of the oil industry in the United States. The news of the discovery was followed by a rush of adventurers from all parts of the country, so that by 1860 more than 100 square miles of territory in the vicinity of Oil Creek had been shown to be productive.Much of the oil which reached the surface was allowed to escape, owing to the lack of storage and transportation facilities. As the explorations were extended new fields were opened along the Allegheny River in Pennsylvania, also in Ohio and West Virginia. The Lima field of Ohio and Indiana was first developed in 1885, while the California fields have become large producers only in the last few years. The discovery made in the Beaumont region of Texas early in 1901, which has been followed by extraordinary development, is the most important event in the recent history of petroleum.

Among foreign countries, Russia is the largest producer of oil and the strongest competitor of the United States in supplying the world'smarkets. Operations have been conducted in this country since 1873. The largest fields are located on the Apsheron Peninsula, Baku being the chief centre of the industry. The distillation of petroleumfrom shales was first undertaken in France in 1834, and was successfully introduced into Scotland in 1850. The importation of shale oil into America led to the use of cannel coal fordistilling; this industry gained considerable importancein the United States previous to 1860, but quickly succumbed when the first wells became productive.

Origin and Geological Occurence. Thegeological history of petroleum and natural gas are closely connected, so that what is said of one practically holds true of the other. Petroleum is always found in sedimentary rocks. For many years it was known only in sandstones or shales, and the term oil-sand was applied to the containingstrata. Subsequently oil was struck inlimestone in Ohio, thus forming a new type ofoccurrence, although one which has since proved to be rather unique.

Petroleum is considered by most geologists to have been derived by the destructive distillation of either animal or vegetable matter contained in the rocks. The products of this distillation have in some cases accumulated in the strata in which they were formed, while in others they have escaped upward into the overlying beds, in some instances even reaching the surface.

Petroleum occurs in all geological formations, from the Lower Silurian or Ordovician up to the Tertiary; it is chiefly of importance in theSilurian, Devonian, and Tertiary rocks. The relation of the distribution of oil to geological structure was not recognized until as late a date as about 1880, at which period geologists began to find the cause of oil accumulation and pressure. Prof. Edward Orton, of Ohio, was the most prominent investigator in this field. In all regions wherepetroleum occurs the strata are not only disturbed, but they are bent into anticlinal or arch-shaped folds. If the rocks are porous the gas tends tocollect at the summit of the anticlinal fold or arch, while the oil collects in the flanks of the fold. Salt water is usually associated with the gas and oil, and, being heavier, accumulates in the flanks of the anticlinal or in the neighboring synclinal folds. There is little use of searching for oil in regions where the strata are flat; and it is rarely found in highly folded regions, for where the flanks of the fold have a dip of more than 10° the bending of the rocks is often sufficient to create cracks through which the oil or associated gas will escape to the surface. The rock in which the oil is found is spoken of as the reservoir, oroil-sand, and it is essential that this rock should be porous. The degree of porosity not only influencesthe quantity of oil which the rock can hold, but it may also influence the rate of flow of the well. Some wells may yield as little as 15barrels per day; others may reach a production of 50,000 or 60,000 barrels per day. The porosity of the oil-bearing formation may also change from place to place and would account for the location of a profitable well at one point and a barren one a short distance from it. In order to prevent the escape of oil from the containing stratum it should also be overlain by a rock of more or less impervious nature. In many wells the petroleum flows to the surface under pressure. Professor Orton believcd that the oil was under hydrostatic pressure; according to his theory, the pressure in different wells of the same basin or pool ought to be nearly constant. In anyregion, however, the pressure usually diminishes with time. While Orton's theory may be true for Ohio, it seems doubtful whether hydrostatic pressure will account for the great oil and gas pressure found in some regions. The quantity of oil which a given territory can yield is often very great, since some sand will hold as much as one-eighth of its bulk in oil under pressure. This means that there is 1.5 inches of oil to every vertical foot of oil-sand, or about 5000 cubic feet per acre.

Character and Composition. Petroleum is a liquid of varying color, being black, brown, red, amber, or straw, and by reflected light often ​appearing greenish in tint. The black oils in theUnited States are obtained from the Trenton limestone of Ohio and from California; thePennsylvania oils are of amber tint. In addition to the hydrocarbons, which are the chief constituentsof petroleum, the following substances may be present: Sulphur, nitrogen, hydrogen sulphide, carbon disulphide, arsenic, and phosphorus. The carbon percentage may vary from 79.5 to 88.7 per cent.; the hydrogen from 9.6 to 14.8 per cent.; the sulphur from 0.7 to 2 per cent., and in rare cases even 3 per cent.; nitrogen from 0.008 to 1.1 per cent. The hydrocarbons of all crude petroleumsfall either into the paraffin or olefin group, those of America belonging chiefly to the first and those of Russia to the second group. The number of different members of the paraffin series present may be very large; some Pennsylvaniaoils, for example, have yielded 18 different paraffin compounds, as well as a number ofsubstances belonging to the ethylene group. The hydrocarbons of the olefin series predominate in the Russian oils and many others. The compositionof crude petroleum from a number of differentlocalities is given below:

The gravity of an oil is most commonlyexpressed in the degrees of the Baumé (B.) scale, on which water has a specific gravity of 10 degrees. The oils from Allegany County, N. Y., run from 38° to 41° B.; from Venango County, Pa., 46° to 48° B.; Warren County, Pa., 43° B.; Lima County, Ohio, 36° to 38° B.; Florence, Colo., 30° B. Russian oils average about 32° B. The lighter oils yield a better quantity of illuminants, while the heavier ones often serve well forlubricating purposes, etc. On exposure to the air many petroleums lose their more volatileconstituents and change to a viscous or even solid condition resembling asphalt. The lightercolored varieties are often quite liquid, while the black or dark oils may be slightly viscous. The temperature at which crude petroleum solidifies ranges from 82° F. in some Burma oils to several degrees below zero in certain Italian oils. The flashing point may be equally low in thelatter, but in others found on the Gold Coast it rises as high as 370° F. The boiling point likewise shows considerable variation, from 180° F. in some Pennsylvania oils to 338° F. in certain oils found at Hanover, Germany.

Distribution of Petroleum. The most noted and most productive field in the United States is the Appalachian, which extends along the westernslope of the Appalachian Mountains, from southwestern New York (and eastern Ohio), through western Pennsylvania into WestVirginia, Kentucky, and Tennessee. The oil-bearing sandstones are partly Devonian and partlyCarboniferous,the latter being especially important in West Virginia. Four fields are recognized in Pennsylvania, the oil varying from amber to dark green. Ohio contains two districts. One of these, the Mecca-Belden field, is of minor importance; a second in eastern Ohio is a westward extension of the West Virginia area. The Lima-Indiana field extends from Lima southwestwardly intoIndiana, lying without the Appalachian region as usually defined. The oil here is carried by the Trenton limestone of the Lower Silurian, the depth being about 1300 feet; it was first discoverednear Findlay, Ohio. The oil is dark and heavy and resembles the Tennessee and Canada oils in its sulphur contents. Farther south oil is obtained from the Carboniferous in eastern Kentucky and in Tennessee. While new pools are discovered occasionally in the Eastern fields, the most important developments in recent years have been in the Southwestern and Western States.

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COPYRIGHT, 1902, DODD, MEAD & COMPANY.

​Oil has been found at a number of localities in the Tertiary rocks of eastern Texas, and several fields, including the Corsicana,Nacogdoches, Beaumont, Elgin, San Antonio, and Sugar Lake, are now being exploited. The firstmentioned supplies both light and heavy oils, which are obtained from depths of 950 and 1175 feetrespectively. The first well put down in the Beaumontfield yielded 75,000 barrels of oil a day, spouting the liquid in a six-inch column to a height of 160 feet; nine days elapsed before the flow was brought under control. The Beaumont oil is a dark asphaltic oil with much sulphur, and is obtained at a depth of 1000 feet. Petroleum has also been discovered in western Louisiana, especially near Jennings, where it is found at a depth of 1800 feet. Southeastern Kansas and northeastern Indian Territory produce some oil from the Cherokee shales and sandstones of the Carboniferous. In Wyoming petroleum occurs in 18 scattered fields, and in formations ranging from the Upper Carboniferous to the UpperTertiary, but mostly in those of Mesozoic age. The Cretaceous sandstone at Florence, Colo., yields a heavy oil which resembles that of Wyoming in being valuable as a lubricant. Oil has also been obtained in moderate quantities at Boulder, Colo. It is obtained at depths of as much as 2850 feet, and has a gravity of 42.5° B. Californiacontains several oil fields in the southern part of the State. The rocks are of Cretaceous to Neocene age. The oil has an asphaltic base, and is chiefly valuable as a fuel. Petroleum is also known to occur in Washington, Arizona, New Mexico,Montana, and Utah. A moderate amount of oil isobtained from Lambton County, Ontario, at a depth of 400 to 500 feet. Cuba is known to have at ​least small supplies of oil, and a limited quantity has been exported from Porto Rico. In Mexico active exploration has been carried on at several points in the Gulf Coast region with the result of finding supplies of good oil around Tampico. It has an asphalt base. Of the South American countries, Peru is the most important petroleum producer, most of the output coming from the Zorritos field. Petroleum is also said to occur in Venezuela, Argentina, and Ecuador, but it is not taken out of the ground to any extent.

Russia is not only the most important foreignproducer of petroleum, but the largest producer in the world, the fields in the Baku region ofSoutheastern Russia supplying enormous quantitiesannually. The greater part of the output comes from the Baku field proper, although important quantities are obtained from the Grosni field, 500 miles north of Baku. Rumania contains several promising oil fields, which occur in the sameformations as the Russian fields. In Germany oil is obtained near Hanover, and also in Alsace, while some is supplied by the Carboniferous rocks of Great Britain, but does not begin to supply the local demand. In Japan petroleum is obtained on the northwestern coast, and some of it is refined. The crude material sometimes yields 60 per cent. of illuminating and lubricating oils. A high paraffin oil is found in Java, and Sumatra, Borneo, and the Burma field of India are important producers. While petroleum is known to occur in the Philippines, little isobtained, and that by primitive methods; theislands of Panay, Leyte. Guimaras, Negros, Bohol, Mindanao, and Cebú all carry some petroleum.

Mining and Transportation of Petroleum.The modern method of drilling for petroleum is similar to that used in sinking gas and artesian wells. The most prominent feature of theoil-drilling outfit is the derrick, which is a tall,pyramid-like wooden frame about 75 feet high, 12 feet square at the base and about 3 feet at the top. The cost of a rig, as it is called, ranges from $200 to $275. The diameter of the well hole is 10 or 12 inches at the surface, decreasing with depth to 5 or 6 inches. In Russia wells are drilled of much greater diameter, and 26 inches is not an unusual size for the beginning of the bore-hole. In many cases the oil does not flow when the oil-bearing rock is struck, and it is customary in this instance to explode a torpedo at the bottom of the drill-hole, whereupon the oil almost immediately begins to pour out of the well, sometimes with tremendous velocity. For details of petroleum mining, see Well-Sinking.

​The question of cheap and rapid transportation of crude petroleum from the wells to the refineriesis one of great importance. At first the oil was transported on carts, later it was carried in barges or by railway in tank cars, but these methods gave place to the system of pipe lines. At the present day the total length of pipe lines transporting Pennsylvania crude oil is probably over 25,000 miles. The pipes, which have a diameterof from 4 to 8 inches, are usually laidunderground and have bends at regular intervals to allow for contraction and expansion. Stations with pumps and storage tanks are placed from 28 to 30 miles apart, the oil being received into the tank at one pumping station and then forced through the pipe to the next one. Since all petroleumcontains more or less paraffin or wax, much trouble is often experienced in the clogging of the pipes, especially in cold weather, and to clear them out an instrument known as the‘go-devil’ is sent through the pipe. This is soconstructed that it is forced along by the moving current of oil and scrapes the paraffin oil from the inside of the tube. Pipe lines have been built from the Appalachian oil region to Jersey City, Philadelphia, Baltimore, Chicago, and Cleveland.

Refining. The refining of petroleum is based upon the separation of the component hydrocarbonsby a process of fractional distillation. This is usually carried out in horizontal cylindrical iron stills, which are surmounted by a dome that connects with a vapor pipe. A common size of still is 30 feet long by 12½ feet in diameter, with a capacity of from 650 to 700 barrels of crude oil. When the latter is placed in the still andsubjected to increasing temperature, the oils pass off in the order of their volatility; the separation is not absolutely perfect, however, as oils of lower boiling point may carry over some higher ones. As the vapor rises it passes to the condenser, a series of iron pipes surrounded by cold water. The distillates are led off into their respective tanks. This process of distillation, which is known as the intermittent system, is the one commonly followed in the United States, and the still requires periodic refilling. In Russia acontinuous system is employed, involving a series of stills, which are heated to successively higher temperatures. The crude oil then flows slowly from one to the other, and from each one there passes off the product volatilizing at the temperatureto which the still is heated.

The process of fractional distillation can bedivided into two parts. In the first part of the process the more volatile products, such as gasolineand other naphthas, are evolved. The residueis then transferred to another still in which the second part of the operation is carried on, the oil being heated to a still higher temperature for the purpose of separating the illuminating and lubricating oils. The condensing apparatus ends in the tail house, where the distillates are conducted to their proper tanks. When thevarious fractions of the distillation are to be kept separate, and of constant composition, a special form of condenser may be used, by means of which the oil is brought into contact with the surface of iron turnings, thereby increasing the evaporation. If the oil contains sulphur it is necessary to redistil it in stills containing copper oxide, which removes the sulphur. Cracking is a term used to denote the process of condensing the heavier vapors in the still, causing them to become superheated and decomposed, and thusobtaining a more complete separation of thefractions, as well as increasing the percentage ofilluminating oil. In the distillation of the oil the lightest constituents pass off first and the heaviestlast. The fractions obtained in the order of their lightness are the following: Cymogene. This is the lightest of all, and since its boiling point is 32° F., it is a gas at ordinary temperatures.Rhigolene. Boiling point, 65° F. Petroleumether. A highly volatile product having a specific gravity of 0.635. It has sometimes been called Sherwood oil. Gasoline. This, properly speaking, is the fraction following petroleum ether, although the name is often applied to a mixture of this and the three previous ones, its gravity thus ranging from 0.635 to 0.690. In ​gasoline proper the boiling point ranges from 90° to 200° F. Naphtha is a name broadly applied to all light distillates, but more especially to those boiling at 80° to 120° F., and whose gravityvaries from as low as 62° B. up to 76° B. Benzine(q.v.) represents the least volatile product of the naphthas and has a specific gravity of about 0.73 (57° to 62° B.), and a boiling point of 120° to 150° F. Ligroine forms a special grade of solvent naphtha of a specific gravity of 0.715, and a boilingpoint of 194° to 248° F. Following the lighter naphthas come the illuminating oils,divided into heavy and extra heavy naphthas; in the process of distillation these may either becarried off separately or together. In the former case, the heavy naphthas may be redistilled and separated into benzine and light distillate. The latter may then be mixed with the extra heavy naphthas in varying proportions to form white oil or export oil. There are many grades ofdomestic illuminating oil or kerosene, which differ chiefly in fire test.

After the naphthas have passed off, the residuumis forced through steam-jacketed filters filled with bone black or fuller's earth; the first portions of the filtrate represent light oils, and are followed by successively heavier ones. When the petroleum belongs to the paraffin group, the residuum is sometimes placed in the tar still for further distillation, and there the heavy vapors are carried over by the aid of superheated steam, the presence of the latter also preventingdissociation of the oil, which if it occurred would be followed by a lowering of viscosity of thelubricating oil and a decrease in the amount of paraffinobtained. The distillates containing the paraffin are freed from the latter by chilling, the effect of this being to cause a separation of the waxy paraffin scales. The oils thus freed from the paraffin are important lubricants, and under this class a number of grades are known as spindleoil, engine oil, summer dark oil, winter dark oil, cylinder oil, valve oil, etc. The residue now left in the tar still is a porous mass of separated carbon, solid decomposition products termed coke. The tar is sometimes used without furtherdistillation for the manufacture of vaseline.

Many of the distillates obtained in the treatmentof crude petroleum contain acid constituentsas well as compounds which in time impart a dark color and unpleasant odor to the distillate. Raw distillates, when used for illuminatingpurposes, also rapidly char the wick and lose their power of being drawn upward by capillarity. It is therefore customary to purify the variousfractions obtained by treatment with sulphuric acid and caustic soda, before they are marketable. The distillate, which has been first cooled to 60° F., is agitated with sulphuric acid in tallcylindrical tanks of wrought iron lined with sheet lead, and known as agitators; about 1½ to 2 per cent. of acid is required. The acid is then washed out with water, and a 1 per cent. solutionof caustic soda added, after which a second agitation takes place, followed by washing.

The percentage of the various fractions yielded by different oils varies. Many Pennsylvania oils yield 8 to 10 per cent. naphtha, 70 to 80 per cent. refined oils, 5 to 9 per cent. residuum and 5 per cent. loss. In the distillation of 100 gallons of crude petroleum there are obtained on the average about 76 gallons of illuminating oil, 11 gallons of gasoline, benzine, and naphtha, and 3 gallons of lubricating oil, while the residuum and loss amount to 10 gallons.

Testing of Refined Oils. Refined oils are usually tested for their color, gravity, flashing and burning points, and sometimes for theirbehavior when cooled (cold test). The color is determinable by inspection. The gravity is a measure of the purity of the distillate. Too large a proportion of the lighter oils renders the product unsafe for illuminating purposes, while too great a percentage of the heavier oils interferes with its free burning qualities. The gravity test is commonly made by placing the oil in a tall jar and inserting a hydrometer marked preferably with the Baumé scale (water has a value of 10 on this scale). The temperature of oil when this test is made should be 60° F. The fire testinincludes the determination of the flashing point, i.e. the temperature to which the oil must be heated in order to produce a momentary explosionof the mixture of inflammable vapor, and of the burning point, i.e. the temperature to which the oil must be heated in contact with the air to take fire and burn on the surface. The burning point is commonly from 6° to 20° C. higher than the flashing point. Kerosene for lightingpurposes should have a flashing point of not less than 110° F., and a burning point of not less than 125°. Both the flashing point and burning point are carefully regulated by law in mostcivilized countries so as to run the minimum risk from explosion. The cold test is of importance for lubricating oils, and is made in order todetermine the temperature at which the oil thickens or becomes cloudy. It can be made by cooling the oil in a small tube and noting the temperature at which the oil ceases to flow when the tube is inclined.

Uses. The two chief uses of the distillates from crude petroleum are for illumination and lubrication, but the various fractions in many cases have special applications. Rhigolene is used as a local anaesthetic; petroleum ether isemployed as a solvent for caoutchouc, fatty oils, and plant principles, and for carbureting air in gas machines; gasoline is employed in the extraction of oil from oil seeds, in carbureting coal gas, in gasoline lamps, stoves, and plumbers' lamps. Naphthas in general are employed as solvents for resins in varnish-making, and in the manufactureof oilcloth. Boulevard gas fluid is a productof 0.68 specific gravity used in street lamps, while benzoline is a deodorized naphtha of 0.70 specific gravity. Benzine is employed for dry cleaning, as a substitute for and adulterant of turpentine for cleaning printer's type, and for dyers' and painters' use. The benzine of the U. S. Pharmacopœia has a specific gravity of 0.67 to 0.77, and a boiling point of 122° to 144°, and therefore represents a higher distillate. Astral oil and mineral sperm oil are specialilluminating oils of high flashing points. Crudepetroleum is much used for fuel purposes inengines. Along the Pacific Coast, especially in southern California, where good coal is scarce, the locomotives consume large quantities of crude oil. Paraffin residue is placed on the market for medicinal purposes under the name of vaseline, petroleum ointment, and cosmoline. It is also used in the manufacture of chewing gum, and for insulating purposes in electric work.

Production. The growth of the petroleumindustry in the United States is shown in the ​following table, which gives the annual productionat intervals from 1859 to 1900:

The production of crude petroleum in the United States in 1901 amounted to 69,389,194 barrels, valued at $66,417,335. Of this quantity, 48.45 per cent. came from the Appalachian field, 31.61 per cent. from the Lima-Indiana area, and 19.94 from the other areas combined. The number of gallons of petroleum and its derivatives exported in 1901 was 1,062,750,306, valued at $71,479,124. This went to all parts of the world, but chiefly to Europe. In this same year the quantity ofmanufactured petroleum exported by Russia was 36.8 per cent. of that exported by the United States. New York is the leading port of exportation, with Philadelphia second. So large has the export trade become that some countries have a large fleet of specially constructed tank steamersengaged in the oil-carrying trade. Up to 1899 the total tonnage of these was nearly 400,000 tons. The world's production of petroleum in 1901 was as follows:

See Shale Oil; Asphalt; Gas, Natural.

Bibliography. General, on Refining and Properties. Thomson and Redwood, Handbookof Petroleum (London, 1901); Redwood, ATreatise on Petroleum (ib., 1901); “Petroleum,”in The Mineral Industry, vol. ii. (New York, 1893); Sadtler, “The Technical Utilization of Petroleum and Its Products,” in The MineralIndustry, vol. iv. (ib., 1895); Folger,“Petroleum: Its Production and Products,” inAnnual Report of Secretary of Internal Affairs,Pennsylvania, pt. III. (Harrisburg, 1892);Series of Papers by Sadtler, Peckham, Day,Phillips, and Mabery on the “Origin and Chemical Composition of Petroleum,” in Proceedings ofthe American Philosophical Society, vol. xxxvi. (Philadelphia, 1899); Peckham, “Petroleum,”Report of Tenth Census (Washington, 1881).

Origin. Orton, “The Origin and Accumulation of Petroleum and Natural Gas,” in Ohio GeologicalSurvey, vol. vi. (Columbus, 1888); Orton, “Geological Probabilities as to Petroleum,” in Bulletin of the Geographical Society of America,vol. ix. (Rochester, 1898).

Distribution. Van Ingen, “Petroleum in New York” Bulletin of New York State Museum, vol. iii., No. 15 (Albany, 1896); Orton, “Petroleum and Natural Gas in New York,” Bulletin of New York State Museum, vol. vi. (ib., 1899); Bishop, “Oil and Gas in Southwestern New York,” New York State Museum, 53d AnnualReport, vol. i. (ib., 1901); Phillips and Carll, “On the Oil and Gas Region of Pennsylvania,”in Second Geological Survey of Pennsylvania,Annual Report for 1886 (Harrisburg, 1887). Consult also many other articles in other volumes of the Second Geological Survey, notably reports iii., xiv. and xv.; White, “Oil in West Virginia,” West Virginia Geological Survey, vol. i. (Morgantown, 1899); White, “The Mannington Oil Field and the History of Its Development,” Bulletin of Geographical Society of America, vol. iii.(Rochester, 1892); Orton, “Petroleum andNatural Gas,” in Kentucky Geological Survey, report for 1894 (Frankfort, 1895); Orton, “The Trenton Limestone as a Source of Petroleum and InflammableGas in Ohio and Indiana,” Eighth AnnualReport U. S. Geological Survey, pt. ii. (Washington,1889); various articles by Blatchley onPetroleum in Indiana in the Annual Reports of theDepartment of Geology and Natural History(Indianapolis), and also the Reports of the OilInspectors in the same volumes; Phillips, “Texas Petroleum,” in Texas University Mineral Survey,Bulletin No. 1 (Austin, 1900); “The New Oil Gusher at Jennings, Louisiana,” in Engineeringand Mining Journal, vol. lxxiv. (New York, 1902); Adams, “The Oil and Gas Fields of the Western Interior and Northern Texas Coal Measuresand of the Upper Cretaceous and Territory of the Western Gulf Coast,” Bulletin of UnitedStates Geological Survey, No. 184 (Washington, 1901); Haworth, “Oil and Gas in Kansas,” KansasGeological Survey, vol. i. (Topeka, 1896); Eldridge, “The Florence (Colo.) Oil Field,”Transactions of the American Institute of MiningEngineers, vol. xx. (New York, 1891); Knight and Slosson, “The Dutton, Rattlesnake, Arago, Oil Mountain, and Powder River Oil Fields,”Wyoming University School of Mines Bulletin No. 4,Petroleum Series (Laramie, 1901); Knight, “Oil in Wyoming,” University of Wyoming, School ofMines Bulletin, No. 2 (Laramie, 1897); Watts, “Petroleum in California,” Transactions of theAmerican Institute of Mining Engineers, vol. xxix. (New York, 1900); Watts, “Oil and Gas Yielding Formations in California,” Bulletin ofthe California State Mining Bureau, No. 19 (San Francisco, 1900).

Foreign. Vaughan, “Bitumen in Cuba,”Engineering and Mining Journal, vol. lxxiii. (New York, 1902); Tanasescu, “Petroleum inRoumania,” Journal of the Iron and Steel Institute,pt. 1 (London, 1901); Spurr, “Mineral Resources of Turkey, Pt. ii., Oil and Gas,” Engineering andMining Journal, vol. lxxiv. (New York, 1902). For Russian petroleum, consult MineralResources, United States Geological Survey, 1900(Washington, 1901). For information regardingforeign occurrences and industry, see also the volumes on Mineral Resources, publishedannually by the United States Geological Survey, and also The Mineral Industry (New York),published annually by the Engineering and MiningJournal.