PETROLEUM. The word "petroleum" (rock-oil;. Germ., erdbl, steindl) is used to designate the forms of bitumen that are of an oily consistence. It passes by insensible gradations into the volatile and ethereal naph-thas on the one hand and the semi-fluid malthas or mineral-tars on the other.
History.Petroleum has been known by civilized man from the dawn of history. Herodotus wrote of the springs of Zacynthus (Zante), and the fountains of Hit have been celebrated by the Arabs and Persians. Pliny and Dioscorides describe the oil of Agrigentum, which was used in lamps under the name of " Sicilian oil," and mention is made of petroleum springs in China in the earliest records of that ancient people. The abundance of petroleum and the fire-temple at Baku on the Caspian have been frequently de-scribed by travellers who have gone overland from Europe to India, from the time of Marco Polo to recent years. Petro-leum in North America was first mentioned by a Franciscan missionary, Joseph de la Roche dAllion, in a letter written in 1629 and published in Sagard's Histoire du Canada in 1636. Peter Kalm described the springs on Oil Creek in his book of travels in North America, published in London in 1772. In 1750 the French commander at Fort Duquesne described them in a letter to General Montcalm, and later, towards the close of the last century, frequent mention is made of oil-springs in correspondence relating to what is now western Pennsylvania, Ohio, West Virginia, and Ken-tucky. In 1765 and 1826 the British Government sent embassies to the court of Ava, in the reports of which mention is made of the petroleum springs and wells near Rangoon on the Irawadi. During the early years of the present century the occurrence of bitumen, and particularly of its liquid forms, was noticed by scientific men and travellers in various localities. In Europe, Boussingault's researches upon the petroleum of Bechelbronn (Lower Alsace) and the discovery of paraffin by Reichenbach attracted much attention. Petroleum was observed and described as early as 1814 in Washington county, Ohio, in wells at that time being bored for brine. In 1819 a well bored for brine in Wayne county, Kentucky, yielded so much black petroleum that it was abandoned. It has continued to yield small quantities until the present time. In 1829 a well drilled for brine near Burkesville, Cumber-land county, Kentucky, yielded such a flow of petroleum that it was regarded as a wonderful natural phenomenon. This well is estimated to have yielded, up to 1860, 50,000 barrels of oil, the larger part of which was wasted. Of the rest a few barrels were bottled and sold as a liniment in the United States and Europe under the name of "Ameri-can oil."
About the year 1847 E. W. Binney of Manchester, Eng-land, called attention to the petroleum discovered at Rid-dings, near Alfreton in Derbyshire, and a few years later he, together with James Young and others, commenced the manufacture of illuminating and other oils from it. The supply of crude material from this source soon became in-adequate, and they then commenced distilling the Boghead mineral that had been found near Bathgate in Scotland. The success attending this enterprise soon attracted atten-tion in the United States of America, and a number of estab-lishments were in operation in the course of a few years, someof them being licensed under Young's patents. In 1851, when petroleum on Oil Creek was worth 75 cents a gallon in the crude state, it was tested as a crude material for the manufacture of illuminating oil by Messrs William and Luther Attwood, and Joshua Merrill, at the United States Chemical Manufacturing Company's works at Waltham, near Boston, Massachusetts, and its merits for that purpose fully established. But its scarcity at that time prevented its use in commercial quantities, and the establishments at Boston and Portland, Maine, under the charge of Messrs Merrill and William Attwood, continued to use Boghead mineral and albertite for a number of years after petroleum was produced in sufficient quantity. Petroleum was refined and offered for sale in Pittsburgh, Pennsylvania, as early as 1855, but the quantity was too small to influence even the local trade; it, however, created a small demand for the crude oil. The well-known fact that brine-wells often pro-duced petroleum led those who sold the " American oil" to embellish the label on the bottles with.a derrick and other accompaniments of a brine-well; and the story is told that the projector of the first well drilled exclusively for petro-leum was led to undertake it through reflecting upon this picture. Some oil from one of the natural springs near Titusville, Pennsylvania, was sent to Professor B. Silliman, junior, of Yale College, and he made a report upon it which has become a classic in the literature of petroleum. This report was so satisfactory that a company was organized in New Haven, and E. L. Drake was sent to drill a well upon land that was leased in the valley of Oil Creek, a short distance below the spot where the city of Titus-ville now stands. The region was then almost a wilder-ness, and many delays were experienced before he succeeded in getting his men and machinery in operation. He was at first thwarted by quicksands and water, but he finally drove an iron pipe 36 feet down to the rock. This device, said to have been original with Drake, has been of great value in artesian boring ever since he used it. After drilling 33 feet on the 28th of August 1859, the drill fell suddenly 6 inches into a crevice, and was left until the next day, when the drill-hole was found to be nearly filled with petroleum. No spot in the entire territory where petroleum has since been obtained could have been selected where the oil was to be obtained nearer the surface. The success of this enterprise led to the immediate drilling of other wells, first in the valley of Oil Creek and its tributaries, and later over the higher land between Oil Creek and the Alleghany river below Tidioute. As this territory began to be exhausted, the region of the lower Alleghany, in Butler and Clarion counties, yielded wells of great richness, and finally the Bradford field in M'Kean county became the centre of production. A careful com-parison of the situations of some of the most productive wells led to the discovery that the areas yielding oil were not irregular in outline, but extended across the country in narrow belts, without regard to the present configuration of the surface. The areas of these belts were in general parallel, and extended in a north-east and south-west direction, 15° to 20° from the meridian. As the exhaustion of the oil-fields of Butler and Clarion counties led pro-ducers to seek a more productive locality, lines were run by compass on the supposed axis of the oil-belt over forest-covered hills for many miles, until they reached the town of Bradford, near which wells had previously been drilled without success. Deeper wells were drilled, and oil was obtained, resulting in the development since 1875 of about 68,000 acres of the most uniformly productive and exten-sive oil-territory yet discovered.
In the province of Ontario, Canada, principally in the vicinity of Enniskillen, a territory of limited extent but great productiveness has been under development for the last twenty years. In the region about Baku and in the valley of the Kuban, at the eastern and western extremi-ties of the Caucasus, petroleum has been obtained for an unknown period, and is now being produced from artesian borings in large quantities. In Galicia and Roumania it is also obtained in commercial quantities. These regions with the United States furnish the petroleum of commerce. Japan, China, Burmah, and Italy have yielded petroleum in quantities sufficient to supply a local demand, but the vast quantity of the American oil and low price at which it is furnished have rendered the production in these coup-tries unprofitable.
Geographical Distribution.Petroleum "was found about one hundred years since in making the duke of Bridge-water's tunnel at Worsley, at Wigan and West Leigh in | the Lancashire coal-fields, at Coalbrookdale and Wellington in Shropshire and Eiddings in Derbyshire, two other coal-fields ; also in a peat-bog at Down Holland, near Orms-kirk, in Lancashire, but never in commercial quantities. The greatest supply has not been more than fifty gallons a day, and even that soon diminished." A tar-spring was known at Coalport, in Shropshire, early in the present century. Although there are extensive deposits of solid bitumen in eastern France and Switzerland, the petroleum springs that occur at Saint Boes, Basses Pyrenees, are un-important. In Alsace, at Lobsann and Bechelbronn, petro-leum has been obtained for many years for local uses. Although reported from many localities in Germany, the only point that has promised to be of any importance is the Lüneburg heath, south of Hamburg. Petroleum is also reported near Hölle, in Dithmarschen, Schleswig-Holstein. On the eastern shores of the Adriaticin Dalmatia and Albaniaand in the Ionian Islands, petroleum springs have been mentioned by the writers of classical antiquity. In Armenia and Persia petroleum has been used for un-known centuries, and it appears to be widely distributed in the mountains that surround the tableland of Iran. In Algeria, Egypt, Kashmir, the Punjab, Assam, Java, and other East Indian islands petroleum is reported. In North America the successful development of the petroleum-fields of north-west Pennsylvania following the completion of Drake's well led in a few years to the drilling of wells in a great many localities where petroleum-springs had been observed. The following so-called " petroleum-fields " have produced oil in commercial quantities more or less valuable.
== TABLE ==
Besides these localities petroleum has been observed over an area 1500 miles long by an unknown breadth in the valley of the Mackenzie and its tributaries, and in New Brunswick, Newfoundland, and other portions of eastern Canada. It also occurs at many different points along the Appalachian system of mountains from Point Gaspe on the St Lawrence to northern Alabama. It has been noticed in Kansas, Missouri, Wyoming, Colorado, and Texas in the United States, in southern Mexico, in the West India Islands, and in the northern states of South America. Petroleum is one of the most widely distributed substances occurring in nature, but an examination of the geograph-ical localities in which it chiefly occurs will show them to be intimately connected with the principal mountain-chains of the world.
Geological Relations.It has been frequently remarked that petroleum occurs in all geological formations, from the Silurian up to the Tertiary. While this is true as a general statement, it is misleading, for petroleum is not uniformly distributed through all formations, but occurs principally in two epochs of geological history; these are the Silurian and the lower half of the Tertiary. The vast accumulations along the principal axis of occurrence in the western hemisphere are found in Silurian and Devonian rocks; the most productive axis of occurrence in the eastern hemisphere lies in the Eocene and Miocene of the Car-pathians, Transylvania, and the Caucasus. In England the small quantity of petroleum that has been observed has sprung from the Coal-measures. In the valley of the Rhone and in Savoy it is in Jurassic limestones. The bitumen of the Apennines, of Dalmatia and Albania, of Roumania, Galicia, and the Caucasus, issues for the most part from rocks that are Eocene. But little is known respecting the geology of the bitumen of Asia Minor and Persia; the Punjab is also Eocene, and the little that is known of the deposits in Burmah and the East Indian Islands indicates that they are of the same age. East of the Mississippi river petroleum has been reported from localities that describe an ellipse upon the border of the Cincinnati anticlinal, which consists of an elevation of Silurian rocks extending from central Kentucky to Lake Erie, with the city of Cincinnati nearly in its centre, slop-ing beneath the newer formations in all directions. Start-ing at Great Manitoulin Island, in the northern part of Lake Huron, it is next reported at Port Huron, Michigan; Chicago, Illinois; Terre Haute, and in Crawford county, Indiana; Henderson, Cloverport, Bowling Green, and Glasgow, Kentucky; and around Nashville, and south-east-wards to Chattanooga, Tennessee, where the Silurian rocks again reach the surface. Turning north, the line extends almost unbroken through the eastern counties of Kentucky into Ohio and West Virginia, into Pennsylvania and New York, the ellipse being completed by the petroleum-fields of Canada. At Great Manitoulin Island petroleum was obtained in the Trenton limestone, at Chicago and Terre Haute in the Niagara limestone, both of which are Silurian. The Kentucky geologists regard the great Devonian black slate as the source of the oil in that State. There it is found saturating sandstones at Glasgow, and in crevices at Burkesville and other points on the Cumberland river. In the neighbourhood of Nashville, where the Lower Silurian rocks reach the surface, petroleum occurs within geodes, which are enclosed in the solid mass of the blue limestone. North-east of Nashville the present location of the oil is found to be in rocks that lie in an ascending series. Around Burkesville it is found in the Upper Silurian, immediately beneath the Devonian black slate. Farther north it lies in the Devonian and Subcarbonifer-ous sandstones, which, in Johnson county, Kentucky, are now partly above the drainage-level of the country. The so-called "oil-break" of West Virginia and Ohio yields petroleum from sandstones that lie within the Coal-measures. Still farther to the north-east, in Pennsylvania and New York, the oil-sands are all found beneath the Coal-measures in the Upper Devonian, while in Canada they again descend to the Lower Devonian. " Petroleum exists in the Cretaceous rocks which extend along the eastern slope of the Rocky Mountains from British Colum-bia to Mexico, and in many of the interior valleys." The bitumen of the Pacific slope, of Mexico, the West Indies, and South America, is Miocene in California and Eocene in Trinidad and Peru. From these statements it will be seen that there is a vast area in the Mississippi valley, estimated at 200,000 square miles, beneath which petroleum has been obtained, the formations of which are nowhere more recent than the Coal-measures. Another vast area, extending from California through Mexico to Peru, and including the West India Islands, yields petroleum from Tertiary rocks; while on the eastern continent a belt of country extends from the North Sea to Java, the bitumen-bearing rocks of which are Tertiary so far as is known. At present the bulk of petroleum produced issues from rocks older than the Carboniferous, while the formations yielding bitumen, in by far the greater number of localities, are of Eocene age. In the great "oil-region" of the United States petroleum occurs in crevices to a very limited extent. In Canada and West Virginia it occurs beneath the crowns of anticlinals, and in Pennsylvania it saturates the porous portions of formations that lie far beneath the influence of superficial erosion, like sand-bars in a flowing stream or detritus on a beach. These strata are not of any particular geological age, but run through a vast accumulation of sediments embraced in all the forma-tions between the Lower Devonian and Upper Carbonifer-ous. They lie conformably with the enclosing rocks, and slope gently to the south-west. The Bradford field in particular resembles a sheet of coarse-grained sandstone 100 square miles in extent, by from 20 to 80 feet in thickness, lying with its south-western edge lowest and submerged in salt water, and its north-eastern edge highest and filled with gas under an extremely high pressure. In Galicia the sandstones holding the oil are very much dis-turbed, while in the Caucasus the deposits of sand are erratic both in regard to position and extent, and lenticular in outline, being enclosed in a formation consisting of stiff blue clay.
Chemistry.The first chemical research upon petroleum was conducted by Vauquelin in 1817 upon the naphtha of Amiano. Prior to the discovery of petroleum in commer-cial quantities, a number of European chemists had made determination of the atomic constitution of several different varieties, and it had become generally understood that the oil consisted of an equal number of atoms of carbon and hydrogen. It has since been determined that some varieties of petroleum contain nitrogen and others contain sulphur and oxygen.- These last-named elements are, however, to be properly considered as components of impurities. The proximate principles of petroleum have been determined and examined chiefly by Schorlemmer in England, Pelouze and Cahours in France, and C. M. Warren and S. P. Sadtler in the United States. Many other chemists have contri-buted valuable assistance to the work. These researches have established the fact that Pennsylvania petroleum con-sists chiefly of two homologous series of isomeric compounds having the general formula C$-'2n,-\-2, at one extremity of which marsh gas is found and solid paraffin at the other (see PARAFFIN). This oil also contains a smaller propor-tion of the olefine series, having the formula CttH2«, with traces in the Bradford oil of the benzole series. Rangoon petroleum contains a larger proportion of both the olefine and the benzole series than Pennsylvania oil. It has been shown that Caucasian petroleum contains the additive compounds of the benzole group which have the same per-centage composition as the defines and furnish an illumin-ating oil containing more carbon than Pennsylvania oils of the same specific gravity. The residues from the manu-facture of petroleum have been shown to contain very dense solids and liquids of high specific gravity, having a large proportion of carbon and possessed of remarkable fluorescent properties. Some petroleums are easily oxidized into asphaltum and kindred products. Colourless illumin-ating oils under the action of light absorb oxygen, which is converted into ozone, and they become yellow and viscid and of greatly impaired quality when the action is prolonged.
Origin.The origin of petroleum has been a subject of speculation among scientific men during the last half cen-tury. It is a subject involved in much greater obscurity than the origin of coal, for, unlike coal, it has no organic structure; hence it can only be inferred upon circumstantial evidence that it is of organic origin; yet such evidence is so strong that few competent judges have ventured to decide otherwise. The arguments in favour of a chemical origin have been advanced almost wholly by a school of French chemists during the last twenty years. They are based upon the results of a class of experiments first inaugurated by Berthelot, in which powerful deoxidizing agents like the alkali metals or iron at a white heat are caused to react with steam and carbonic acid. The hydrogen of the water and the carbon of the carbonic acid, having been deprived of their oxygen, unite in the nascent state to form a mix-ture of oily fluids closely resembling petroleum. Sufficient quantities of these oils have been prepared to prove their identity with each other and with crude petroleum. Be-fore concluding from this circumstance that petroleum is the product of similar reactions, it is necessary to assume a condition of the earth's interior concerning which we know nothing ; and, while the theoretical chemistry of the earth, based upon the nebular hypothesis, does not forbid such possibilities, there are other considerations relating to the origin of petroleum based upon the known rather than the possible that render the assumption that petroleum is of mineral origin forced and unnecessary. It is found that, when shale, coal, peat, wood, or animal matter, in fact any recent or fossil organic matter, is subjected to destructive distillation at low temperatures, there is ob-tained among other products an oily fluid which chemistry shows to consist chiefly of the same compounds of carbon and hydrogen as are found in Pennsylvania petroleum. There are other petroleums, however, occurring in Canada, Tennessee, and other localities somewhat different in com-position, which are often found under conditions that make it extremely difficult to account for their origin upon any hypothesis that does not regard them as a product of the decomposition of animal remains. They fill the cavities of fossil corals and orthoceratites in Canada and of geodes in Tennessee, in all of which the oil appears to be hermetically sealed until the rock-mass is broken. The formation in which these oils occur consists of thickly-bedded Silurian limestones that were probably deposited in a deep sea at a somewhat high temperature, in which vast quantities of sea-animals perished and became buried. It is therefore most strictly in accordance with observed facts to assume that these oils, in whatever manner they may have been produced from the original animal remains, are indigenous to the rocks in which they are found. These indigenous oils do not occur locally in considerable quantity, although the aggregate amount scattered through any formation in which they occur can easily be shown to be large.
In those localities, notably north-western Pennsylvania and eastern Ohio, where petroleum occurs in large quan-tity, it occurs quite uniformly, saturating heavy beds of uncemented sandstone. This sandstone is overlaid with an impervious shell of slate, containing much silica, that holds down both the oil and gas within the sandstone under great pressure, not locally in cavities but over wide areas. The sandstone is also, so far as can be ascertained, underlaid with a vast formation of shale more than 1000 feet in thickness, containing large numbers of fossil animals and such a quan-tity of fossil sea-weeds that Dr J. S. Newberry has suggested that the Silurian ocean here contained a veritable sargasso sea. This shale, so filled with the remains of fucoids, has been several times submitted to destructive distilla-tion, and has yielded as high as 50 gallons to the ton of distillate oil that was in many respects scarcely to be dis-tinguished from crude petroleum. During the present century the French chemical geologists have held that all forms of bitumen are the product of metamorphism. Prominent among these may be mentioned Daubrée, who in his Observations sur le Métamorphisme has shown the strict correspondence between his laboratory experiments, in which all forms of bitumen were produced, and the operations of nature. No evidence appears to be lacking to show that those operations of nature in which heat, pressure, and steam have joined, usually denominated by physicists "metamorphism," when acting upon strata con-taining organic remains, are an adequate origin for petro-leum as it occurs in the oil-regions of Pennsylvania and in Galicia. Petroleum occurs on the western slope of the Appalachian system from Point Gaspe on the Gulf of St Lawrence to northern Alabama, and there it is most abun-dant in the neighbourhood of strata in which there is the greatest accumulation of organic remains. The accumu-lations of sediment from which this mountain-system was constructed were deposited in a current whose course was parallel with the axis of the system, and, as has been so fully shown by Professor James Hall (Paleontology of New York, vol. iii., Introduction), these sediments were deposited in great thickness and of very coarse materials in the north-east, gradually thinning and increasing in fine-ness as they reached the Mississippi valley in the south-west. Prom the latest conclusions of American geologists it may be inferred that originally the eastern border of these deposits lay over a region now covered by the Atlantic Ocean. When the elevation took place that brought the metamorphic rocks of New England, New York, Pennsylvania, and Virginia to the surface, the eastern border remained submerged, while the western border was brought above the sea-level. The facts that concern petroleum are found in the comparatively un-disturbed and nearly level position of this western border, in which the rocks holding the petroleum lie at present, like sand-bars in a current, and the further evidence that they afford that the metamorphic action which has altered nearly all the formations of the eastern border became extinct along a plane that descended deeper and deeper from the surface as the western slope of the system is traversed. This evidence further shows that along the western borders of the system, although the rocks and the coal that they enclose are unaltered near the surface, at the same time vast areas of the fucoidal shale and even limestones containing indigenous petroleum may have been invaded by the heat-action and their volatile con-tents distilled at great depths. This distillate, being forced up by heat and hydrostatic pressure, would natur-ally accumulate in any overlying bed of rock porous enough to receive it. In Galicia, Roumania, and Tran-sylvania the metamorphic core of the Carpathians is flanked by beds of fucoidal shale rich in the remains of marine animals, which are intercalated with the beds of sandstone that contain the oil. This hypothesis, which regards petroleum as a distillate, includes the facts as thus far observed, is in harmony with scientific possi-bilities, and is reasonable, as it does not require any ex-traordinary assumption of either chemical or geological con-ditions. While the maintenance of any particular theory concerning the origin of petroleum is primarily of very little practical value, it is indirectly of value to conclude whether by some deep-seated chemical action the oil is at present being prepared in the laboratories of nature, or whether its generation has been long since completed. If a correct interpretation of the phenomena observed in rela-tion to petroleum leads to the hypothesis that the fluid is in most instances a distillate, and especially in those localities where it is most abundant, then the conclusion is inevitable that the generation of petroleum is practically completed, and the deposits are vast natural storehouses which when once emptied are as completely removed from future production as a worked-out bed of coal.
Methods of Production.While petroleum has been pro-duced for an immemorial period in Persia, China, Japan, Burmah, Baku, and Galicia, and while the primitive methods employed in each country in its production furnish interesting subjects for study, it is scarcely possible in this article to do more than indicate in a general man-ner how the vast quantities produced at the present time in the United States and Canada are brought to the surface, stored, and transported. In both Galicia and the Caucasus, which, with Canada and the United States, now furnish the petroleum of commerce, the ancient methods of production are being rapidly superseded by those employed in America. In the United States the development of oil-territory has acquired a habit that has become well defined, and has been repeatedly exemplified during the last twenty years. The first step is the sinking of a test or "wild-cat" well outside the limits of any proved productive territory, the progress of such well being eagerly watched not only by those who pay for it but also by many others who hope to profit by the experi-ment. The striking of oil in such a well is the signal for a grand rush, and a speculative floating population invades the place. After a time the speculative phase is succeeded by that of settled development. The oil-territory has be-come outlined. The sagacious ones have secured control of the most profitable tracts, while the floating element has moved on to a new field. Between the period of active development and absolute exhaustion comes that of decay, when the derricks are rotting and falling to wreck, and when property that has ceased to be productive has been sold at an extravagant price, and after accumulating debts has been abandoned. Finally the wave passes over and nature restores as she restores after the ruin of battle-fields. A visit to Pithole city, which in 1865 was, next to Philadelphia, the largest post-office in Pennsylvania, showed in 1881 fields of maize and timothy where some of the most famous wells had been, and of the city a score of houses tumbling to decay and not an inhabitant. It is not to be inferred, however, that any of the sections into which the oil-regions have been divided entirely cease to produce oil. There are wells now producing within sight of the spot where Drake drilled the first well; but large tracts cease to be centres of speculative investment, the old wells cease to be remunerative, and the new wells no longer hold out the possibilities of a grand lottery.
Wells are sometimes drilled by the owners of the land, but the larger part are drilled under leases. These leases are drawn with a great variety of conditions, but they usually stipulate that the lessor shall pay to the lessee a certain portion of the oil produced, the amount varying from one-tenth to one-fourth in proportion to the supposed richness of the territory. One well lo five acres is considered as many as a judicious arrangement will allow, but many wells have been drilled much closer, and in some instances several wells have been drilled on one acre. The oil-sand of different localities varies as it occupies different geological horizons. The Venango oil-sand extends from Tidioute in Warren county to Herman Station in Butler county, Pennsylvania, a distance of 62 miles. It is uniformly a conglomerate of smooth white quartz pebbles, from a quarter to three-quarters of an inch in thickness. In other districts of the United States, Canada, and Galicia the oil-sand is a true sandstone of varying colour and texture. In the Caucasus the sand is fine, and resembles a quicksand, as it rises with the oil and accumulates around the wells.
When the location of a well has been determined, a derrick or "rig" is built, which consists of the derrick itself and a small house for an engine, with the necessary foundation for both. This foundation is made of heavy timbers dovetailed and keyed together. The derrick consists of a framework firmly braced in the form of a truncated pyramid, and about 70 feet high. At its base are two large reels, upon one of which the drilling cable is coiled and upon the other the sand-pump rope. At one side of the derrick a heavy post, called the Samson post, is framed into the main sill, upon the top of which rests the walking-beam, one end of it being connected with the engine of from 12 to IS horse-power, whilst the other supports the drill. When the engine is in motion the walking-beam alternately raises and drops the drill. The boiler is made like the tubular boilers usually employed on locomotives, and is placed at a distance from the well to prevent the ignition of the gas that often accompanies the oil. The engine should be reversible, and so drilling tools temper - screw the walking-clamped by the worked dowm-The free end d, which is bar of iron firmness to the upper link of I steel, the slots
slack ^ =s
by the use of cords and pulleys. A string of is represented in fig. 1. First we have the a, which is attached directly to the end of beam, into the jaws of which the cable is set-screw b, and the long screw of which, c, is ward by the driller as the rock is penetrated, of the cable is fastened to the rope-socket screwed into the sinker-bar e, that is, a solid about 20 feet in length which serves to give tools. The sinker-bar is screwed into the the jars. The jars, /, consist of two links of of which are 21 inches long, with cross-heads 8 inches deep, in consequence of which the links have 13 inches of play. The lower link of the jars is screwed into another long iron bar called the ya?:??' auger-stem, g, which is in turn screwed to the bit or drill h. The jars are the centre of action, and the manner in which they per- US-form their work may be best i^§-explained, perhaps, in this -SJ^S way. Suppose the tools to "Ss^e have been just run to the LJ3 bottom of the well, the jars . closed, and the cable slacked, the men now reel up the slack until the sinker - bar Q rises, the "play" of the jars ^ allowing it to come up 13 SS^gsSS inches without lifting the " auger-stem ; when the links come together they back about 4 inches and O
clamp the cable into the
^BOTTOM OF =
temper-screw. If now the Ql^^B^SisS vertical movement of the Jjj gB walking-beam is 24 inches, . <o .1 the sinker-bar rises 4 inches, ^ when the cross-heads of the Ulggg^^r links come together with a dggjjgjlj _ smart blow ; then the auger- J =pgjjgjjg|j=g stem is picked up and lifted <o gfaais? 20 inches. On the down- gl&gil|g^= stroke the auger-stem falls m j^^s^=gg 20 inches, while the links I ^=s=i
slide 4 inches carrying the ^ SUBR-S^
to strike on the down-stroke, Ul 'Jg! while the blow of the up- * stroke prevents the drill =s== \ from becoming wedged into _ any seam or crevice into which its weight might drive it. When the tools are all ^ ready for operation, either a SF, wooden conductor is placed 0;S° perpendicularly in a sort of^f_°0-
.sinker-bar down 24 inches. CO 8B=fgSKgH^g5^|g§§K=i= The links are never allowed n
9 Sfflt s-
shaft sunk to the bed-rock, log <>r an iron tube called a , " drive-pipe " is driven upon Jj; it through the soil. In either case great care is taken to start the well perpendicularly * ?<?S
?5/2 HOlEoSoo"« %
°o 0 0 0 °0°
to the derrick-floor. The tools are swung into position <
0~Ct Q C
from the top of the derrick, ^^sgsJ^IS^ and the free end of the cable ^jjjalfesa is coiled around the shaft of WlVo? the reel in such a manner
tightened the tools are lifted,
J C3 o cr^>
and when it is loose the reel- loJSSS'^S^w -c shaft revolves wdthin the ^SiS^S^SX^ coils. By holding the cable o2S5i3S2j iirmly the tools rise, and as 'S^rSS^k'-it is loosened they fall. The .; -ao-gS.^'-"»1 well is started in this man- 5! ^?^>'W-v ner and carried down until J P<Tt*'V*g4
the string of tools can be & = ~~
suspended beneath the walk-
FiS- 1.String of Tools.
ing-beam,when a cable as long is the supposed depth of the completed
well is wound upon the reel, the end carried over a pulley at the top of the derrick and then fastened into the rope-socket, the temper-screw attached, and the drilling continued to the bottom of the well. Day and night the machinery is kept in motion, one driller and one engineer and tool-dresser work from noon until midnight, and another pair work from midnight until noon. The driller, with a short lever inserted in the temper-screw, walks round and round to rotate the drill. He watches the jars, and at intervals lets down the temper-screw. When the screw is run out or the drill needs sharpening, he arranges the slack cable so that it will run freely over the pulley and proceeds to " draw out." The cable is undamped from the temper-screw and the engine disconnected from the walking-beam and attached to the cable-reel. When all is ready the long cable is reeled up and the tools drawn out. The bit is replaced by one newly sharpened, and after the well '_~'%SS^. has been sand-pumped the tools are again lowered and =2-g; drilling resumed. When the drilling proceeds without ac-cident the work is exceed-ingly monotonous.
From the top of the bed-rock to a point below the surface-water of the region, the well is drilled of th same diameter as the in-terior of the drive-pipe. This point is usually from 300 to 400 feet below the surface. At this point the _ drill-hole is tapered, and a SKgliB'TSM;^ pipe armed with a steel shoe Hfe °" is ground into the tapered hole to a water-tight joint. The inside diameter of this casing-pipe is 5| inches, and
below it the well is earned
down 5J inches in diameter =
to the bottom. The casing
pipe excludes the fresh sur-
face-water, and only water
enough is put into the well -to wash out the drillings, ===V unless salt water is encoun- sf
tered. The casing-pipe be- gjfe =
comes a permanent fixture, ==^===1 into which is introduced the SgsSSt' . .
2-inch pipe, through which
the oil flows or is pumped. This 2-inch pipe may be in-1 troduced or removed at plea- fUjjg sure, without disturbing the casing-pipe or drive-pipe, or letting water into the well upon the oil.
O O O O j£f o
When drilling has been completed the w:ell is tor-pedoed. From one to twenty-five gallons of nitro-glycerin are lowered into the well in tin cylinders and exploded, usually by percussion. The effect of firing such a large amount of this powerful explosive is not apparent at the surface, but soon a gurgling sound is heard ap-proaching from beneath ; the oil rises from the well and falls first like a fountain and then like a geyser, forming a torrent of yellow fluid, accompanied by a rattle of small stones and fragments agigo,»jr*» -^r--gr
of the canister in a shower *:~-^:=s*J=^ ==
of spray 100 feet in height. Kg- 2.Pumping Well.
The generation of such an enormous volume of gas in a limited area, the walls of which are already under a very high gas-pressure, and which is held down by 2000 feet of motionless air, must be followed by an expansion into the porous rock that drives both oil and gas before it, until a point of maximum tension is reached. The resistance then becomes greatest within the rock, and, reaction following, oil and gas are driven out of the rock and out of the well until the expansive force is expended.
Figs. 2 and 3 show the general arrangement of pumping and flowing wells. After the well is torpedoed it is prepared for flowing. A section of 2-inch pipe, per- forated with holes, which serves as a strainer, is low- ered into the well and other sections coupled to it, until a sufficient length is intro- duced to reach from the bot- tom to a point above the oil- sand. An indiarubber packer is then attached in such a manner that within it the pipe that is above it slides in that which is below it, and the rubber is forced against the sides of the drill- hole with the weight of 1200 to 1800 feet of 2-inch pipe, thus making a gas-tight joint. The pressure of the -ySfioTTOM o> gas within the oil-sand and - 8727 C>O- o o~oo~r Oi O- O - OQ-Q-Q- Cl- o ooQao-Oc> !OCr-o O O OO - I <zro -o-o osj-oo-o~ ocr -v- ty- oOOf"i - below the packer forces the oil to the surface. As the flow diminishes, a pump- barrel is introduced to the bottom of the well and the oil is lifted to the surface. Gas-pumps are also used to ^=i^z=rji remove the pressure of the " atmosphere from the well and rock. In some of the older districts from twelve to forty wells are attached to one engine, and pumped by '== what is called a "sucker-rod" connexion. In West Vir- ginia Ave different horizons of sandstone have yielded oil. A well was put down there in 1865 to the "first white oak sand," 255 feet in depth, and pumped at inter- vals for fifteen years ; it was then reamed out to 8 inches in diameter, and from the bottom of the old well was carried down 4^ inches in diameter to the third sand. A tube was inserted with a packer at the bottom of the 8-ineh hole to stop oil' the heavy oil of the first sand. Through this oil of a speci- fic gravity '79 (45° B.) was pumped from the third sand, and through a second tube, introduced beside the first to the bottom of the old well, oil of a specific gravity (27° B.) was pumped from the first sand, both pumps being simultaneously worked by the same walking-beam. The first-sand oil was worth seven dollars a barrel, while the third-sand oil was worth only one dollar a barrel. . The average duration of _
the profitable production of--" : Z _~. . '-,,771
an oil-well is estimated at F* 3Plowing Well,
five years. This period is subject to great fluctuations, as there are wells in the Cole Creek district of the Bradford field that were abandoned in two years, while wells on Triumph Hill, Venango county, where the sand is 125 feet thick, have been pumped fifteen years. The yield of some single wells has been enormous. A well in Donegal township, Butler county, Pennsylvania, produced more than 110,000 barrels in ten years, and twelve wells, of wdiich this was one, on the same farm produced over 750,000 barrels.
In Burmah and other Eastern countries petroleum was stored and transported in.flasks and jars. In the United States it was for many years transported in barrels made tight for oil by being coated on the inside with a stiff solution of glue. Later, it was transported on the rivers in bulk barges, and on the railroads in tanks upon cars. These tanks were at first made of wood, but they have lately been made of iron. The usual form is a plain cylinder, 24 feet 6 inches long and 66 inches in diameter, having a capacity of from 4000 to 5000 gallons. These cars are also used in the Caucasus. At the present time, in all the regions pro-ducing petroleum in commercial quantities, the bulk of the crude oil is transported through pipe-lines, which consist of lines of pipe carried across the country, often for hundreds of miles, through which the oil is forced by powerful pumps under a pressure of from 1000 to 1600 lb to the square inch. Each well has a tank into wdiich the oil flows from the well, and from which it is carried in a 2-inch pipe by gravity to a pumping station, where it is pumped into the "main line." Main lines run out of the oil-regions of Pennsylvania to Cleveland (Ohio), Pittsburgh (Pennsylvania), Buffalo (New York), tud New York, Philadelphia, and Baltimore on the Atlantic coast. They are constructed of 6-inch pipe, the joints of which are screwed into couplings like sections of gas-pipe. During recent years the production of petroleum in excess of any demand for it has led to the storage of vast quantities (30,000,000 barrels in 1882) in iron tanks of enormous size. Many of these tanks are owned by private individuals, but the majority belong to the pipe-lines. There are 1375 iron tanks connected with the united pipe-lines, ranging in capacity from 1000 to 38,000 barrels, and representing a total storage capacity of 38,000,000 barrels. These tanks are frequently fired by lightning or other accidents, and when burning present a spectacle of unsurpassed grandeur.
The bulk of the trade in crude petroleum in the United States is conducted through the pipe-lines and their certificates. When oil is received into the line from a well, the amount is ascertained and passed to the credit of the well-owner on the books of the company, less 3 per cent, to cover loss in handling. This oil is held like a bank-deposit, subject to transfer on a written order. When such an order has been "accepted" by an officer of the company it becomes an "acceptance" or "certificate," and is then negotiable like a certified cheque. As the exchanges deal only in certificates of 1000 barrels they are made of that amount so far as is possible. When oil is delivered by the pipe-lines a pipage charge of 20 cents per barrel is paid and a storage fee of $12'50 per 1000 barrels per month must be paid at least once in six months. The issuing of certificates by the pipe-lines has made speculation in oil, brokerage, and exchanges possible to an extent vastly beyond the requirements of any actual trade in the oil itself.
About 250,000,000 barrels of petroleum have been produced in the United States and Canada from 1859 to 1884. No reliable statistics are to be had of the production in other regions, but of late years the Caucasian fields have yielded about 5,000,000 barrels per annum. The total annual production for 1883 cannot be far from 35,000,000 barrels.
Technology.The technology of petroleum is quite simple. In the crude state it enters largely into mixtures with other oils, tallow, lead, soap, graphite, &c., that are chiefly used for lubrica-tion. Crude petroleum is also filtered through charcoal. Crude oils that are too fluid for lubrication are reduced to the required consistence by partial evaporation, both by exposure to the sun in shallow tanks and also by distillation of the more volatile portion in stills. Such oils are called "reduced oils." In the technology of petroleum by distillation a great variety of details are employed by different manufacturers, but in general they may be treated under the three heads of destructive distillation or "cracking," distilla-tion with superheated steam, and distillation in vacuo. The stills used vary greatly in respect of form and capacity. Formerly stills holding 80,000 gallons were used, but recently they have been constructed of a capacity of from 40,000 to 48,000 gallons. They are ordinarily made either in the form of plain cylinders 30 feet in length and 12 feet 6 inches in diameter, and set horizontally in banks of three or more, or there may be an upright cylinder 30 feet in diameter and 9 feet in height, set vertically with numerous fire-boxes arranged around the circumference. Another form of still is an upright cylinder holding about 1000 gallons, heated from beneath and furnished with a steam-coil immersed in the body of the oil. In this coil the steam is superheated to the tempera-ture of the oil, and is then allowed to escape into it, by wdiich means the overheating of the oil is prevented and the distillation assisted by the mechanical action of the steam in lifting the oil-vapour out of the still. Another form of still is a vacuum still, in which a partial vacuum is maintained by a pump. The top of the still is usually constructed with a high dome, into which the vapours rise and from which they escape into the condensers. The condensers usually consist of a large number of 2-inch pipes immersed in water contained in a long trough. The distillation commences at a very low temperature and proceeds at a constantly rising temperature, the distillate steadily increasing in specific gravity. The last portions distil at nearly a red heat, and are nearly solid at ordinary temperatures, with a specific gravity above 900°.
The oil is first allowed to settle in large tanks, when about 1 per cent, of water and sediment is removed. It is then pumped to stills into which "live" steam is introduced. Distillation com-mences at once and is allowed to proceed until the specific gravity of the distillate reaches 74 (60° B). The oil in this condition is called "gas-oil," and is used to a limited extent in the manu-facture of illuminating gas. The distillate is crude naphtha, and is redistilled and divided into (1) rhigolene cr cymogene, having a specific gravity of '62 and boiling at 65° Fahr.; (2) gasolene, specific gravity -66 (90° to 80° B.); (3) G naphtha, specific gravity 70 (80° to 68° B.); (4) B naphtha, specific gravity 72 (68° to 64° B.) ; and (5) A naphtha, specific gravity 74 (64° to 60° B.). Below 60° goes to illuminating oil. The crude oil from which the naphtha has been removed is then put into a suitable still and distilled until the distillate has a specific gravity of -81 (40° B.). This distillate is crude illuminating oil. The oil remaining in the still may then be "cracked" by destructive distillation, or may be distilled for lubricating oil. If it is to be "cracked" the fires are slacked and the distillation allowed to proceed slowly, in consequence of which the vapours of the heavy oil are repeatedly condensed upon the dome of the still and made to fall back upon the hot oil beneath. The result is the production of a large volume of permanent gas, chiefly marsh gas and hydrogen, a distillate of suitable specific gravity for illuminating oil, and a heavy tarry residue, called "residuum," that remains in the still. By this method of manipulation the crude oil is converted into crude naphtha, crude illuminating oil, and residuum, while the gas is burned as a waste product. The residuum is run out of the still and sold to manufacturers of lubricating oil. If the oil is not to be cracked, the heavy oil, from which the illuminating oil and naphtha have been removed, is often distilled with superheated steam and treated for lubricating oil. If simply distilled and treated with chemicals after removal of the paraffin, the oil is called in the United States "paraffin oil." The crude paraffin oil is placed in barrels in an ice-house, and, after it has been several days at rest, paraffin crystallizes from it. The paraffin is removed by pressure, and may be purified by any of the methods described under PARAFFIN (p. 242 above). The oil from which the paraffin has been pressed may be subjected to a further distillation in a steam-coil or other suitable still, and deprived of certain oils that boil at a high temperature but have a pungent and offensive odour. When drawn oil', the oil remaining in the still is found to be light-coloured and nearly tasteless and odourless. It is called "deodorized neutral heavy hydrocarbon oil," and is found to be a very valuable lubricating oil. The distillate above mentioned after treatment is called " mineral sperm," and is used as an illu-minating oil on cars and steamboats, where a more volatile oil would be objectionable. Any of these distillates, from gasolene to the most, dense, lubricating oil, may be purified by filtration or by treatment with acids and alkalis. Filtration is usually applied to the different grades of naphtha to deprive them of disagreeable odour, for which purpose gravel and both wood and animal char-coal are used, either separately or together. Lubricating oils are often filtered through animal charcoal to deprive them of both colour and odour. The dense vacuum residues recently prepared under the name of cosmoline, vaseline, &c, are filtered through animal charcoal while hot and perfectly fluid. Oils are treated with chemicals in high cylindrical tanks of small diameter, where they are thoroughly mingled by means of air forced into the bottom of the tank under pressure. These agitators often hold 50,000 gallons. The illuminating oils are usually treated with 5 per cent, of oil of vitriol at a temperature of about 60° Fahr. The acid " sludge," consisting of the oil of vitriol combined with the impuri-ties of the oil and forming a black tarry liquid, settles to the bottom of the tank and is drawn off. The oil is then agitated with water, then treated with a solution of caustic soda, and finally washed with water containing caustic ammonia. Hydrochloric acid is used to a limited extent, and nitric and chromic acids are used to destroy fluorescence in dense oils. Those illuminating oils especially that are prepared by cracking are thrown after treatment, and while warm, in a thin spray into a large tank. This causes a small amount of very volatile oil produced by cracking to be evaporated, and brings the oil up to test. Finally the oil is exposed under a skylight in large shallow tanks until it has become perfectly clear from settling of all impurities. The acid "sludge" is for the most part sold to manufacturers of commercial fertilizers or restored by evaporation and used over again. More than 45,000 tons of oil of vitriol were used in 1880 by the manufacturers of petroleum in the United States. The alkali sludge is thrown away. The following table shows the average percentage of commercial pro-ducts obtained from crude petroleum of 79 (45° B.) from Pennsyl-vania, Ohio, &c.
Lubricating Oils.Crude petroleum and the heavy distillates from petroleum, finished either by treatment or by filtration, have been slowly winning their way with consumers of lubricating oils for the last twenty years, and may now be said to have a recognized value. This result has been due as much to improved processes of manufacture, and consequently to improved quality of the pro-ducts, as to a recognition of their merits. When properly prepared, and exempt from volatile matter and offensive o±lour, they are found to be possessed of great endurance, to be free from a tendency to gum, and to be incapable of spontaneous combustion. When mixed with animal and vegetable oils liable to spontaneous combustion, these oils prevent it. They are therefore now in large demand, a demand wdiich is likely to increase as new applications are found for them and their quality is improved.
Illuminating Oils.Oils of this class manufactured from petro-leum have nearly superseded the use of other illuminating fluids throughout the world. They are largely sold in Great Britain under the name of "paraffin oils" ; in the United States they are called "kerosene," and on the European continent "refined petroleum." The different qualities are known as " water white," "standard," and "prime," and are further distinguished as "low test" and "high test" oils. The characters chiefly relied on in the trade are "colour" and "test." The colour should be as light and free from opalescence as possible. Colour is, however, a matter of little importance except as it indicates unskilful manufacture of the oil. The " test " is of paramount importance, and indicates the tempera-ture Fahr. at which the oil will give off a sufficient amount of vapour to ignite explosively when the oil is properly tested. While the methods of testing petroleum vary greatly, the apparatuses used for that purpose may be divided into three classes. The first class is designed to ascertain the tension of the vapour given off by a given sample at a certain fixed temperature ; these are chiefly used in France. The others are designed to show at what temperature a given amount of oil, usually half a pint, will give off a sufficient amount of vapour to form an explosive mixture with the air above the oil. These are divided into " open testers," in which the oil is heated in an open vessel, and "closed testers," in wdiich the oil is heated in a closed vessel. The tester invented by Sir F. A. Abel (see PARAFFIN , p.239) has been adopted in Great Britain and her colonies, wdiile in the United States and on the Continent a great variety are in use. The numerous accidents, many of a frightful nature, and involving great loss of property and often of human life, that have followed the use of illuminating oils which had not been properly freed from the volatile products of the petroleum, have led in most European countries and many of the American States to the enact-ment of stringent laws forbidding the sale or use of oils the test of which does not come within the prescribed legal limits. Very valu-able researches on thé flashing of oils have been made by Dr C. F. Chandler of New York, and by other American chemists. Dr Chand-ler showed that oils burning in lamps of ordinary construction in a room the temperature of which was below 90° Fahr. failed to reach an average temperature of 100° Fahr. In metal lamps, particularly "student lamps," the average temperature was several degrees higher than in glass lamps, a fact wdiich shows glass lamps to be safest in this respect. Dr C. B. White of New Orleans has examined illu-minating oils with respect to the amount of volatile material that, when added to good oil, will render it dangerous. He found that from 1 to 5 per cent, of the ordinary naphthas of commerce would render illuminating oil of the best quality extremely danger-ous. Five per cent, of crude naphtha reduced the flashing point from 118° to 70° Fahr. These researches have all demonstrated the wisdom of English legislation on this subject, but unfortunately have not been productive of equally good results in the United States. Petroleum legislation is there in a very unsatisfactory con-dition. The very worthless law passed by Congress in 1867 has long been repealed, and no other has been substituted for it. A number of the States (seventeen in 1880) are without legislation in reference to this subject, while legislation in other States is based upon local influence rather than fixed principles, and ranges in its requirements from extreme laxity to unreasonable exaction, in con-sequence of the lack of intelligent national Governmental action. Nearly all the nations of continental Europe have petroleum laws in the main based upon an intelligent appreciation of the subject, and but little inferior to English legislation.
The Uses of Naphtha.The lightest products obtained from petroleum are rhigolene, which is used in surgery, and cymogene, which is used as the volatile fluid in ice-machines. Gasolene is the lightest fluid obtained in considerable quantity, and is used in automatic gas-machines for the carburation of gas or air. The question of increasing the illuminating power of gas (see GAS, vol. x. p. 101), by causing it to absorb fluid hydrocarbons, was discussed as early as 1832, but it was only after petroleum furnished a cheap and suitable fluid that inventors succeeded in securing results of any value. While hundreds of machines have been patented in England, America, and continental Europe for accomplishing this purpose, it is only quite recently that an American inventor, Dr Walter M. Jackson, has succeeded in constructing a machine that satisfactorily meets all the requirements of the problem. His metrical carburetter measures both the fluid and the gas or air in such a manner that the least amount of the hydrocarbon fluid required to produce the effect sought is furnished to thè gas, and the whole is immediately absorbed. By this means a uniform car-buration is secured, furnishing a gas of uniform quality, that never contains a sufficient amount of fluid to admit of condensation in any part of the apparatus. Both crude petroleum and the products of its manufacture have been used as a material for the manufacture of gas by distillation. The different qualities of naphtha are used in mixing paint, in the manufacture of oil-cloths for floors and of varnishes, as a solvent for gums and resins, in the preparation of alkaloids, in the manufacture of india-rubber, in washing wool, and in removing oils and grease from seeds and textile fabrics.
Petroleum as Fuel.In the region of the Caucasus and on the Caspian Sea, where other fuel is scarce and dear and petroleum is plentifnl and cheap, the latter is used with complete success on both steamships and locomotives. Petroleum and its products have been used with practical success in the manufacture of iron in the United States. Both illuminating oil and naphtha are now very widely used in stoves; but naphtha-stoves are extremely dangerous, and their use should be prohibited by law. In the valley of the Euphrates, near Mosul, petroleum is used as a fuel in burning lime.
Petroleum in Medicine.Although petroleum has been used as a remedial agent for an unknown period in the countries where it is a natural product, its physiological effects have never been very fully investigated. Barbados tar, Haarlem oil, Seneca oil, and American oil, all consisting wholly or in large part of crude petroleum, were sold by apothecaries for years before petroleum was obtained by boring. They were mainly used as liniments for external application, particularly in rheumatism. The oil of the Alleghany valley early had a local reputation as an internal remedy for consumption, and it has lately been prescribed for bronchitis. The most volatile product of petroleum obtained by distillation, called rhigolene, has been used to produce local insensibility, by means of the intense cold resulting from its rapid evaporation ; and the same fluid when inhaled as vapour or the gas escaping from fresh oil will produce an intoxication or insensibility resembling the effects of laughing-gas, resulting in death if its action is pro-longed. The products of petroleum that have proved most valu-able in medicine are the filtered paraffin residues sold under the names of cosmoline, vaseline, &c, that are now so widely used as ointments, either plain or medicated. They are of about the con-sistence of butter, with very little taste or odour, and will keep indefinitely without becoming rancid. These valuable properties have caused them to almost entirely supersede all other prepara-tions containing animal or vegetable fats.
Looking towards the past, it may be said that petroleum has attained universal diffusion as a lighting agent ; it is fast displacing animal and vegetable oils as a lubricator on all classes of bearings, from railroad - axles to mule - spindles, and also where other oils are liable to spontaneous combustion ; it is very largely used as fuel for stoves, both for heating and cooking ; it is very successfully used for steam purposes when other fuel is scarce and petroleum plentiful ; it is likely to be used for the production of pure iron for special purposes ; and it has become a necessity to the apothecary as petroleum ointment. Looking towards the future, wdiat assur-ance have we that these varied wants, the creation of a quarter of a century, will be satisfied ? While it is not probable that the de-posits of petroleum in the crust of the earth are being practically increased at the present time, there is reason to believe that the supply is ample for an indefinite period. Yet the fact is worthy of serious consideration that the production of petroleum as at present conducted is everywhere wasteful in the extreme.
There are very few works that treat exclusively of petroleum. An article in the Bull, ds la Soc. Gioì, de France, xxv., gives the best résumé of the mention made by classical writers. Travellers overland to India and Persia have usually described Baku (see Kaempfer, 1712 ; Hanway, 1743 ; Foster, 1784 ; Kinnier, 184S). On the occurrence of petroleum in Burmah, see Journals of the Em-' berates to the Court of Ava, Symes (1795), Crawfurd (1826), Yule (1855) ; in Persia, Carl Ritter's Erdk. v. Asien, 1840 ; in Japan, B. S. Lyman's Reports, Geolog. Survey of Japan,lS~i-7ö ; in Galicia.Von Hauer (1853), Fötterle (1853,1859,1862), J. Noth (1873), Bruno Walter (1880), in Jahrbuch der K.-K. Geo. Reichsanstalt; in Roumania, Von Hauer, Geologie Siebenbürgens, 1863; H. Coquand, Bui. Soc. Geol. de France, xxiv. 505, 1867 ; in Canada, T. Sterry Hunt, in Reports of Geol. Survey of Canada of various dates, 1S63 -73; in Pennsylvania, J. F. Carll, Reports, I., II., and III., with maps, Second Geological Survey of Pennsylvania, 1S74-1880. On the chemistry of petroleum, see 0. M. Warren, in American Journal of Science and Chemical News; Shorlemmer, in Quar. Journal of the Chemical Society; Pelouze and Cahours in Ann. de Chimie et de Physique ; Berthelot in the same, all at various dates, 1863-1880. On the origin of petroleum, see Lesquereux, in Trans. Am. Phil. Soc, xiii., 1866; J. S. Newberry, in Ohio Ag. Report, 1859 ; T. Sterry Hunt, in Chem. News, vi. 5 et sq.; Byasson, in Revue Industrielle, 1876; Mendeljeff, in Bull. Soc. Chim. de Paris, 1877. On testing petroleum, see John Attfleld, in Chem. News, xiv. 257; F. Crace Calvert, Chem- News, xxi. 85; C. F. Chandler, in American Chemist, ii. 409 ; Boverton Redwood, in English Mechanic and World of Science, xxii. 335, 1875 ; F. A. Abel, in Chem. News, xxxv. 73. On the general subject, see T. Sterry Hunt, " History of Petroleum or Rock Oil," in Canadian Naturalist, , vi. 245 ; Chem. News, vi. 5 ; Report of Smithsonian Institution, 1862 ; J. Lawrence Smith, in Report to the Judges of the Centennial Exposition, Philadelphia, 1876; S. F. Peckham, monograph on petroleum, in- cluding bibliography of petroleum and allied subjects to 1881, in Reports of the Tenth Census of the" United Stales. See also, for an account of wells at Baku, Engineering, 22d February to 16th May 1884, London. (S. F. P.)
The above article was written by: Prof. S. F. Peckham, M.A., U.S. Census Commissioner.