THE object of this paper is to discuss, within the smallest compass—1st, the composition and qualities of coal oil; 2d, its manufacture, use in the arts, and statistics of trade; 3d, the history of its discovery as a natural production; and 4th, the theory of its origin favored by geologists.

All oils are combinations of hydrogen and carbon. They burn by the addition of oxygen, for which carbon has a greater affinity than for hydrogen under the circumstances attending combustion; whereas, under the circumstances attending life or the energetic creation of cellular tissue, the affinities are seemingly reversed, and hydrocarbons are produced; but, in fact, while the inhaled air oxydizes one portion of the blood, carbon, another portion, protected from oxydation, is uniting with the fluids of the body and forming fat or oils. Hence the hydrocarbons, i. e., the solid, fluid and gaseous oils, characterize the animal and vegetable kingdoms; and wherever they are found in the rocks, even of the oldest date, they must be accepted as proofs of the former existence of life at the surface as it then was. Hence, also, the division into animal and vegetable oils, and an uncertainty whether some pi’ oils may not fall into the former category.

Most oils in a state of nature contain other ingredients and impurities. The solid coals contain water and small quantities of nitrogen, sulphur, phosphorus, lime, and the alkalies, with considerable quantities of earthy bases forming their ash. The rosins contain sometimes one-third of oxygen. The liquid oils are sometimes made up as much of oxygen as hydrogen, as, e.g., the oils of sweet almonds, linseed, walnut, olive, fish, potatos, castor bean, &c., the first containing 77.4 carbon, 11.5 hydrogen, 10.8 oxygen; the last, 65.0 carbon, 10.6 hydrogen, 24.3 oxygen. Some oils, like that of the codfish, employ their oxygen for various acids, such as oleic, margaric, butyric, acetic, fellinic, cholinic, bilifellinic, phosphoric, sulphuric, all of which are present together in that oil, with small quantities of iodine, chlorine, bromine, soda, lime, and magnesia.

In oils distilled from coal, such as Kyanol and Leucol, nitrogen instead of oxygen exists in a proportion almost double that of the hydrogen—77.3 + 7.6 + 15.0.

The various proportions in which the hydrogen and carbon unite cause the production of various oily principles, to which various names are given, as Petrolene, C¹⁰ H⁸, (88 + 12;) Benzoene, C¹⁴ H⁸, (91 + 9;) Asphaltene, C²⁰ H¹⁶ O³ (75 + 10 + 15;) Paraffine, C²⁴ H⁵⁰, (85 + 15;) Naphthaline, C¹⁰ H⁴, (94 + 6.).  When these principles combine they form, e.g., the Asphalt of Bechelbronn, considered by Boussingault to be a union of Petrolene 85.4 + Asphaltene 14.6.  Every locality seems to furnish peculiar varieties of oil, due to the variety of these combinations and suited to different purposes in the arts; and the oils coming from different geological horizons differ much. The oils from south of Lake Erie are more explosible than those from the Canadian peninsula. The color ranges from straw, through amber, to jet black, and the consistency from the fluidity of naphtha to the viscidity of tar. Some oils are greenish, and others reddish in hue. Their specific gravities range on Beaume’s hydrometer from 46° to 26°, (sp. g. 0.90.) The American samples tested in Manchester by O'Neil were generally below 0.816. The range of volatility or the limit of explosibility is equally great. Of the samples tested by the Manchester Sanitary Commission, two formed an explosive vapor with air at 60° Fahrenheit, four at 100° Fahrenheit, three at 120° Fahrenheit, twenty at 150°. Nine samples out of thirty-two were pronounced dangerously unsafe. Specific gravity was no test of safety; nor was the boiling point, since, for example, coal naphtha boils at 260° Fahrenheit, but instantly explodes at 32° Fahrenheit. The British government has lately legislated virtually to prohibit the importation of those oils which explode at or under 100° Fahrenheit.

Pure unoxydized petroleum or naphtha becomes oxydized by exposure in the earth into the thicker or solid asphalts or bitumens, as the pure hydrocarbons of the tree oxydize and harden into resin or gum. Sterry Hunt considers the mean composition of petroleum to be equal equivalents of hydrogen and carbon, quoting the analysis of Uelsman, De la Rue, and Müller, and explaining, after Bischot, how the buried vegetation of the past would be eonverted by simple evolution of marsh gas (air being excluded) into bituminous coals and anthracite, without the intervention of a high temperature.

When steam is passed through tar it takes along and condenses afterwards naphtha 9 parts in a hundred; of the remainder,60 parts are dead oil, and 31 parts pitch. The naphtha is divisible in basic oils, acid oils, and neutral oils. To purify it sulphuric acid is added; it throws down the basic oils in the form of “sludge,” from which the coal tar colors are produced. The most volatile portions of the naphtha are the acid oils—carbolic acid, C¹² H⁶ O² and cressylic acid, C¹⁴ H⁸ O², which, when united, form creosote. Solid carbolic acid is the most powerful disinfectant. Treated with nitric acid it forms carbazotic acid, a beautiful yellow dye, as well as a powerful antiperiodic substitute for quinine. The third portion of the naphtha contains the neutral oils—benzol, toluol, xylol, cumol, cymbol, &c., &c., hydrocarbons of different volatilities. Benzol, C¹² H⁶, boiling first, (at 177° Fahrenheit,) is the most useful of these substances, being also obtained easily by simple distillation with steam. With nitric acid it forms nitro-benzol, the substitute now for bitter almonds, and the basis of our tar colors; for with water and iron (C¹² H⁶ (N O⁴) + 2 H O + 4 Fe) there results aniline, (C¹² H⁷ N,) throwing down peroxide of iron. Aniline is a compound ammonia, in which phenyle (C¹² H⁵) replaces one of the three (H + H + H) + (N) in ammonia. From aniline is obtained mauve, magenta, roseine, azuline, blue de Paris, &c., &c., composing the series of blues and reds, which, with the yellow before described, make up the coal-oil rainbow.^*1

The manufacture of coal oil has been essentially deseribed, and some of its uses in the arts hinted at in the previous section. But the production of the oil itself from coal, peat, boghead cannel, cannel shales, and other bituminiferous minerals, required a manufacture, previous to the discovery of the well oil, which consisted radically in a coking process, during which the volatile ingredients distilled over. The first patents for this process in England date 1694 and 1716. Dr. Clayton’s experiments, by which he obtained by distillation “a phlegm, a black oil, and an incondensible spirit,” were published in 1739.  Oil distilled from stone is mentioned in Lewis’s Materia Medica, 1761, and its only practical application seems to have been to medicine. A French patent was granted to Chervan in 1824. But when Reichenbach, of Moravia, published, in 1830-’31, the nature of the various products of the destructive distillation of coal, and described paraffine first got from wood tar, distinguishing it from naphthaline, the basis of illuminating gas, then the attention of western chemists was aroused to the importance of the subject. In 1832 Blum and Moneuse patented, and Lawrent and Selligue began to investigate, the coal oil gas manufacture, their publications running from 1834 to 1845, exhausting the description. The specification of the patent of March 19, 1845, (Brevets d’ Invention, new series, iv., 30, translated in Du Buisson’s specification, No. 10,726, English Patent Office) is pronounced by Hodge incomparable.

James Young, of Glasgow, in 1847, introduced the distillation process into England, and applied it to boghead cannel, from which he obtained, in 1854, an annual yield of oil equal to 8,000 gallons, selling for £100,000, most of which was profit. In 1854 the Kerosene Oil Works, on Long Island, introduced the distilling process into America, and in 1856 the Breckenridge Oil Works, at Cloverport, Kentucky, distilled from cannel coal found there. By the close of 1860 there were 25 factories in Ohio; 6 in Kentucky; 8 or 10 in Virginia; 10 in Pennsylvania; 1 in St. Lonis; 5 near New York city; 1 at Hartford; 4 near Boston; 1 at New Bedford, and 1 in Portland, each averaging perhaps, 300 gallons of light oils per day; the boghead cannel yielding 75 refined from 130 gallons of crude oil per ton, and the American cannels 60 from 117. The Albert coal yields, however, 75 from 110. Now that the natural crude oil issues from the earth in such abundance, the first distilling process is abandoned, and these factories are occupied in refining only. It is, therefore, not necessary to describe the various forms of retort—D-shaped, iron or earthen, rotary. &c.. or the method by coke pits and condensers, or by kilns.

The refining process requires stills holding, say, 1,500 gallons of crude oil, made of boiler plate, with cast-iron bottoms two inches thick, on which the coke crust is deposited eight or ten inches deep, and is used as fuel after being removed. The heat continues twenty-four hours, and rises gradually to 800° Fahrenheit. A steady flow of oil proceeds from the end of the worm, the condensation of paraffine in which, towards the end of the process, is carefully prevented. Of the whole oil 88 to 90 per cent. comes over, and is then further purified with 5 to 6 per cent of sulphuric acid in “agitators.” Three thousand gallons of oil are kept stirred for a while, and then left to settle, the salts being tapped at the bottom. Agitated again with water, and again tapped from below, the oil is agitated a third time with strong alkali, washed again, and then transferred to the second set of stills like the first. Thus is produced, first, the limpid merchantable illuminating oils below 0.820, constituting from 30 to even 90 per cent. of the whole; then follow heavier oils sold to the machine shops and railroads, or re-distilled into light oils and paraffine; finally comes over the dark-colored paraffine oils, which, when left to stand cold in vats exposed to air, deposit paraffine in silvery scales, to be itself pressed and purified with acid, hot water, and alkali. The illuminating oils are deprived of odor by standing for some days in shallow vats over alkaline solutions. Light destroys also the color, but yellowish oil at 60 cents is worth more for lamp use than colorless oil at 75. (Hodge.)

Ammonia is extensively manufactured from the English gas-water, which contains it in combination with the volatile acids, sulphuretted hydrogen, and carbonic acid, and in the form of chloride of ammonium. Ten gallons of this water are distilled from a ton of Newcastle coal. The sulphide and carbonate are reduced by muriatic acid. Four thousand tons of the crystallized muriate are made annually in England. Benzine or eupion, one of the products of coal oil distillation, more explosive than turpentine, has supplanted the latter in the arts since the great rebellion has diminished almost to nothing the production of the southern pine forests. Hence explosions and conflagrations are more numerous. The demand for benzine in England has become unlimited, especially in early and late spring. It is quoted at 2s. 6d. to 2s. 9d. per gallon in casks. American, i.e., United States petroleum, containing much more benzine than Canadian petroleum, rules $10 a ton higher on that account.—(Liverpool, September 20, 1862.) The lubricating oils sent over to England have been as yet but the stingy remains of the absorbing demand in the United States, and are complained of as very mucilaginous, only semiliquid or else altogether too light. The oilometer, and not the hydrometer, should be the guide, ranging sperm at 45°, olive, rape and lard at 27°, 28°, as at the two extremes of practical lubrication. This lowest density, however black, if free from grit, will fetch £15 per ton; green, £17 10s. to £20; brown, £20 to £22 10s., and yellow up to £30.—(Philadelphia Coal Oil Circular, 1862.)

Mr. Dollfuss, of Mulhouse, applies Lebel’s asphalt oil to the inner surface of boilers and heaters, detaching thereby cale crusts, cleansing a 45-horse power boiler with 20 pounds of oil.  Repairs to the boiler are less frequent.—(Franklin Institute Journal, 1862, p. 399.)

As a fuel, petroleum enters into numerous French patents. The people of the Caspian mix it with clay; the Norwegians with sawdust and clay. The refuse charcoal of the French furnaces is mixed with charred peat or spent tar, and tar or pitch is added, and the whole ground and coked. As an illuminating agent coal oil is fast supplanting the animal and vegetable oils. It has always been a lamp oil of India. It lights the streets of Genoa; but its natural odor is so disgusting that its use in Europe was, for a long while after its discovery in Lombardy, interdicted. Since the refining process was discovered, the trade has spread to every city of the Old and New World, and the annual number of patents for new forms of lamp and new kinds of candle shows how completely the kerosenes and paraffines are banishing the whale oils and tallows from the market. The outlet for the coal oil wax in England and on the continent is said to be very large, not less than twenty tons per week being condensed from boghead cannel alone. “The superiority of the petroleum over the paraffine wax is admitted by consumers of every kind, insolubility being the proof of merit.” The cold weather in America is favorable to this manufacture.

Before going on to the supply and demand, which is especially governed by the call for an illuminating agent, it must not be omitted that coal oil, crude, has been always a medicine; in more general use in eastern countries, and in ancient times, because magical qualities were ascribed to it. So also among the North American Indians it has always been a great medicine, and the white settlers have learned to prescribe Seneca oil for many diseases.  Flowing from the solid rocks, it has offered healing virtue without money and without labor.

The number of persons handling coal oil is estimated at from 30,000 to 50,000.  Its effect upon the health has been a subject of much speculation. Mr. E.G. Kelly, a chemist, writing to the Scientific American, says that his men sleep and live in the factory and enjoy remarkably good health, some of them becoming fleshy and robust who were not so before. Weak lungs and asthmatic constitutions find great relief from inhaling the petroleum vapour.  [Neither a scientifi nor an unbiased account. -ASC]

The natural supply of coal oil must now be described. Its history will come in the following section. It has rendered the manufacture from coal, &c., needless; it leaves the refining machinery still at work, and multiplies their stills and vats indefinitely. The quantities of crude oil produced by nature are astonishing. The earth literally spouts oil as a whale spouts brine. The Empire spring sent its oil up to a reservoir three hundred feet above the level of its mouth. The Phillipps well yielded at first three thousand barrels of oil daily, while others around it were also yielding from five hundred to fifty barrels each per day. Previous to July 10, 1862, this well continued to yield from 500 to 600 barrels per day for three months. The Excelsior well flowed 500 barrels per day. The wells on Oil creek alone are estimated as at present producing nine hundred thousand barrels per annum. In Canada three hundred Enniskillen wells, on Black creek, in a plot of two square miles, produce a still larger amount, the minimum yield being ten barrels, of forty gallons each, per day, while one of the wells spouted for many days after it was finished from ten to twelve thousand barrels per day. Another was only second to it in profusion, and, with five or six others, has continued for several months to pour forth continuous uniform floods of the precious liquid, much of which has run to waste here, as in older oil regions, from improvidence in not preparing reservoirs, and from the physical impossibility of procuring an adequate supply of barrels.  Empty oil barrels were, as late as November, 1862, returned from Philadelphia to Pittsburg, en route for the oil region, in immense numbers, at a freight of a dollar a barrel. Villages of barrel-makers have sprung up in the different oil regions, just as cities of potters line the banks of the Irrawaddy, for it requires 6,000 hands to turn out 15,000 barrels per day. There were in July, 1862, thirty-one flowing wells on Oil creek, in eight miles above its mouth, yielding four thousand barrels daily, and it is said that instances are not uncommon of pumping wells becoming suddenly flowing wells, and thereby largely increasing their production. In estimating the magnitude of this new supply, it is well to compare the fact that the entire production of the whale fishery of the world, in one of its most prolific years, was not quite four hundred and thirty thousand barrels of sperm and whale oil together.

Whether the natural supply of rock oil will be diminished in coming time is a question of moment to the speculator, and of interest to the economist and geologist. The force with which new borings often permit the deep-set reservoirs of oil and gas to evacuate themselves, would seem itself to state the physical impossibility of its continuance; and experience has shown that all the older wells slowly diminished their supply. Hall states, in describing the old Freedom spring, in Cattaraugus county, New York, that a well was dug 14 feet deep, 18 feet distant, which afforded at first a large supply of oil, but soon the old and the new springs died away together. Few, perhaps none, of the old salt wells of the Sandy, the Kanawha, the Monongahela, Conemaugh, Alleghany, Beaver, and Muskingum valleys have been retained in full working condition, except by being deepened from time to time. The boring being carried further down every few years. new supplies of brine and oil and gas have been the consequence. The fiercest blowing and spouting wells of the last two years have become comparatively quiet. There is every geological reason for believing that the number and the age of neighboring wells are the two elements of the calculation to determine their capacity.

When a comparison with other regions of the world is instituted, the same conclusion is arrived at. The five hundred and twenty springs of Yananghoung, on the Irrawaddy, yield now only one hundred and twenty thousand gallons of petroleum per annum. Cases of sudden exhaustion also have occurred, when wells, beginning to blow off gas, have, in a few days, become quite dead in all respects. It is also asserted that, in every case of conflagration, the burning well has ceased its yield of oil, as if internally injured, by the cracking of the walls or by the loss of gas. On the other hand, old wells, exhausted by long practice and abandoned, have become refreshed by rest and profitable.

The growth of the supply at present is enormous, whatever may be its future diminution. A railroad is building from Oil City for its sole accommodation. The Erie railroad, which carried only three hundred and twenty-five barrels to New York in 1859, carried 134,927 in 1861, and 278,923 in 1862— 5,364 carloads; of 52 barrels each; equal to 11,156,920 gallons, worth $2,510,302.  The demand, like the demand for coal itself, must always run ahead of the supply which it calls after it. The consumption of coal oil for the world was estimated to be, in 1860, fifteen millions of gallons; in 1861, twenty millions in 1862, fifty millions. The London Times roughly estimates the export to Europe alone, in 1863, at fifty to sixty millions.  The low prices ruling early in 1862 sent trial cargoes all over Europe, to the extent of five millions, and established the trade in every city. The experiments with Thompson’s patent for making gas, at St. Catharine’s, Canada West, and at Homer and Cortland, New York, proving that cheap illumination^*2 was to be got from coal oil, increased at once the European demand.

Of this quantity, about 1,600,000 gallons went to Liverpool, 1,100,000 to London, 900,000 to Antwerp, 700,000 to Havre, 600,000 to Bremen, 240,000 to Hamburg, 200,000 to Marseilles, 170,000 to Cork, 130,000 to Queenstown, 260,000 to Cuba, 300,000 to Australia.

The range of prices from month to month, not only at the distant centres of consumption, but at the centres of production, is extraordinary, both for the length and speed of its movement. The opening of new wells, the destruction of others by fire, the losses sustained in the artificial communication by water, and the alternate drain and glut of the market, have together kept the traffic in coal oil a hazardous speculation. In London, November 28, 1862, crude oil sold in barrels at £19 to £19 10s., and immediately afterwards, on receipt of American news, went up to £22; refined being 2s. 6d. to 2s. 9d. In Liverpool £22 were refused in large lots, and a new rise took place to £24; refined, 3s. In Pittsburg, the accidents of the river and of Oil creek make the quotations dance up and down three prices. On December 13, 1862, crude oil in barrels sold there at 33 to 35 cents, and in bulk 30 to 324 cents; refined: pale straw, 70 to 75 cents; white, 80 cents. That day at Titusville, the emporium of the northwest Pennsylvania oil region, 500 barrels of crude oil sold at $12 50, and 1,500 more at $13. But at the wells the price varied from $5 50 to $7 50, according to location; the barrel itself being charged $2 75 to $3 extra, and hauling to Titusville $3 to $3 50 more.

The following table will show through what curves the Philadelphia prices ran in 1862, as given in the January (10th) number of the Philadelphia Coal Oil Circular, to the editor of which we owe so much for making the history and character of the subject clear.

When we speak of the discovery of coal oil, in reference to late events, it must not be mistaken for a modern invention. The extraordinary attention drawn upon it by the discovery of a more abundant supply, by artificial wells, since the August of 1859, has made its previous history of comparatively little interest to one class of minds, but, on the other hand, has invested that previous history, to philosophic eyes, with all the charm of an archaeological investigation. Did not the builders of Babel use clay for bricks and slime for mortar? (Gen. xi,, 3.) It is evident from an examination of any of the ruins of Mesopotamia, that asphaltic mortar was the bed into which their alabaster wainscot pieces were set, and with which their vast terraces were compacted, and probably their roofs protected; the use of which so abundantly, only facilitated their destruction when the torch was at last applied. The pitch used was made by evaporating petroleum. That of Babylon we know was obtained from the sulphur, brine, and oil springs of Is; the products of which are still sold in the village of Hits. The story of the catastrophe of Sodom and Gomorrah, if not originated, was perpetuated by the vast accumulations of rock oil in the centre of the Dead Sea, as on the surface of a heated, simmering brine vat, where it is hardened by oxydation and drifted to the surrounding shores. A similar phenomenon—a lake of pure petroleum—elicited the amazement of the Spaniards who discovered Trinidad.

Oil springs, in fact, have been known and esteemed, and even worshipped, in every age and many countries. Herodotus describes a bitumen spring in Zacynthus, Zante, one of the Ionian Islands; and probably this spring sufficed the Egyptian nation for their incessant religious use of petroleum for mummies, the embalmment of which is amusingly described in Hunt’s Merchants’ Magazine for 1862. The “Greek fire” of more modern times was probably compounded of petroleum from the Zantean springs. Dioscorides tells us that rock oil was collected in Sicily and burned in the lamps of Agrigentum. The classic home of naphtha is Baku, a high peninsula on the western shore of the Caspian Sea, containing thirty-five villages and twenty thousand souls, rocky and sterile, without an attractive spot, without a stream, without one drop of sweet water except what falls directly from the clouds, and without a tree.  But coal gas rises everywhere from a soil saturated with naphtha, and numerouns volcanoes in action discharge volumes of mud. From the time of Zoroaster the naphtha of Baku has been sent all over Asia for the service of the sacred fire of the Parsees. The liquid streams spontaneously through the surface, and rises wherever a hole is bored. But especially at Balegan, six miles from the capital village, the sides of the mountain stream with black oils, which collect in reservoirs constructed in an unknown ancient time; while not far off, a spring of white oil gushes from the foot.

Upon their festival occasions the people pour tuns of this oil over the surface of the water in a bay of the Caspian, and then set, as it were, earth, sea, and sky in a blaze of light.  Sometimes far grander exhibitions take place naturally. In 1817 a column of flame, six hundred yards in diameter, broke out near Balegan, and roared with boiling brine and ejaculated rocks for eighteen days together, until it raised a mound nine hundred feet in height. Of course, the population use the oil for light and fuel and coat their roofs with it. A clay pipe or hollow reed steeped in lime water, set upright in the floor of a dwelling, serves as a natural and sufficient gas-pipe. The Ghebers bottle it for foreign use; the Atecshjahns fire with it their lime-kilns and burn their dead. No wonder the religious sentiment of oriental mystics was entranced by such a land of fire as Baku, where in the fissures of the white and sulphurous soil the naphtha vapors flicker into flame; where a boiling lake is covered with a flame devoid of sensible heat: where after the warm showers of autumn the surrounding country seems on fire; flames in enormous volumes rolling along the mountains with incredible velocity, or standing still expectant; where the October and November moons light up with an azure tint the entire west, and the Soghda-ku, Mount Paradise, the eastern buttress of the Caucasus, covers its upper half with a glowing robe; while if the night be moonless, innumerable jets of flame, isolated or in crowds, cover all the plains, leaving the mountains in obscurity. The Gheber and the chemist here may worship side by side. All the phenomena of distillation and combustion, under varying barometric and thermometric conditions of the atmosphere, may be studied; for none of this general fire burns unless when captured and applied to human uses in the lamp or stove or kiln. In the midst of this devouring element—through this world in flames—men live and love unharmed, tend sheep, plant onions, sleep, are born and die, as in more prosaic regions. The reeds and grass are in nowise affected by the flowing oil or by the burning gas. In fact, Rottiers, the traveller, thought the whole phenomenon electric, when he noticed that the vacuum in his thermometer tube seemed to be especially full of flame, and that the east wind put to quiet the whole exhibition; with which fact we may compare the curious discoveries of Moffat with his phosphorous thermometer, published in Silliman’s Journal, December, 1862, p. 437, as bearing on his theory of two normal opposite air currents. From an equally remote era the Burman empire and northern Hindostan have received annual supplies of rock oil from the wells of the Himalayan valley of the Irrawaddy, through Rangoon; and it has always been a favorite drug in the Indian pharmacopoeia.

In Italy, the oil wells of Parma and Modena date back nearly two centuries, the year 1640 being that assigned to tleir discovery. The springs of Ammiano have long lighted the streets of Genoa.

In France, oil springs have been known from time immemorial at Clermont and Gabian; and in Canton Neufchatel; and in Bavaria, Germany.

In the English coal mines, of course, the coal-oil gas—the dreadful fire-damp—was always a well-known demon to the mining population; but in 1659 Shirley, perhaps first, describes it to the reading public as an illuminating gas. In 1733 Sir James Lowther laid pipes along the mines and burned the gases at the surface of the earth. Dr. Clayton’s retort experiments, to which we referred above, at the beginning of section 2, were six years later still. His “incondensible spirit” he burned in bladders for the amusement of his friends, as did Dundonald again in 1786, and Murdock in 1792. But the lighting of London streets and houses with gas came not till 1842. Twenty years have elapsed, and there are in Great Britain and Ireland 1,015 gas-works, with a capital of $90,000,000, charging an average of $1 80 per thousand cubic feet to small consumers, and deducting from five to thirty per cent. for heavy consumption. Some of these companies pay twelve per cent. dividends, and many of them ten per cent. The average capital of British gas-works is said to be nearly twenty per cent. less than that of American works.

In America the history of coal oil commences with the use which the white settlers found the Indians made of it for medicine, for paint, and for certain religious ceremonies. The settlers adopted its medicinal use alone, and retained for more than one affluent of the Alleghany river the Indian name of Oil creek. The one which has become so celebrated lately,enters the river a few miles above the town of Franklin. The oil was collected both by the natives and the whites by spreading blankets on the marshy pools which line the edges of the bottoms at the foot of steep hill-sides, or even mountain walls, such as hem in those valleys and support a table land of coal measures above.  The remains of ancient pits, with notched logs for ladders, show how long the product has been valued by the aborigines. But although in all the valleys of western New York and Pennsylvania, eastern Ohio and Kentucky, and northwestern Virginia, the evidences of the almost universal existence of the Seneca oil was known to the early settlers, its actual abundance underground was not dreamed of. Even long after the era of salt-well boring had begun, the isolated cases of spouting wells did not teach the truth as it is now known. Some of the oldest salt wells of the Pittsburg region, it is true, and of the Kanawha valley, yielded not only brine, but also oil and gas in great abundance; and in more than one place, and with a partial and temporary success, the gas was tubed off and led beneath the boiling vats for fuel. But it was too fitful in its escape to be relied upon; the oil which accompanied it was of no use, and when abundant a great nuisance. Hildreth describes the quantities of petroleum spouted from the salt well bored in 1819, in the valley of the Little Muskingum, in Ohio, and the tremendous explosions of gas which interrupted, sometimes for days together, the flow of brine. It was this fitful and ungovernable vis a tergo, having its unknown seat of power in the deep, which made every effort futile to employ the gas as fuel.

Travellers, however, report that this has been successfully done by the Chinese salt-makers for many centuries. As for the oil, continues Hildreth, it made for itself a local commerce, beginning to be in demand for lamps in workshops and manufactories, and the suggestion was already made that it would serve to light the streets of the cities of Ohio. It is not a little singular, says Mr. Hodge, that with the sources of supply thus pointed out, and the useful application of the petroleum understood, its value should have remained unappreciated, and, at the expiration of more than thirty-five years, be at last perceived through the progress of experiment made upon the distillation of bituminous shales and coal. But the fact seems to stand thus the natural coal oil was a disgusting and imperfect thing, and there was neither the pressure of necessity nor the favor of science applicable, in Ohio, in the beginning of the century, to its purification. The destruction of the whale fishery, the increase of the railroad system, with its rolling gear and workshop machinery, and the coming in of lard oil as a substitute for whale oil, all had to intervene between the inception and the performance of the coal oil drama.

It was in 1847 that Mr. Young, in Glasgow, (the most intimate friend, by the way, of the African traveller, Livingstone,) had established his purification of petroleum from the Ridding’s mines in Derbyshire, boghead cannel, common coal shales, peat and solid bitumen, and introduced the use of these mineral oils to such an extent that a search for the native article, long known to exist, was set on foot in earnest. The oils of the coal region of America at once commanded principal attention. The first practical movement in this direction was not made, until, in 1854, Messrs. Eveleth and Bissell, of New York, secured the right to the upper spring on Oil creek, and organized a company. Still, three years passed before Mr. Bowditch and Colonel Drake, of New Haven, began the first Titusville boring, striking the oil stratum at seventy-one feet depth in August, 1858. The drill sank suddenly into a cavity, and the oil rose within five inches of the surface, and was pumped off at the rate of, at first, 400 and afterwards 1,000 gallons per day. The news spread. The wildest speculation soon raged. Every acre of land in the valley, and part way up the steep hill-sides, for ten miles south of the boring, as far as to the junction of Oil creek with the Alleghany river, was bought up by eager contestants for a fortune sure to be realized in a few months. Hundreds of wells sank speedily to various depths. The once quiet, beautiful valley became a noisy den, a hideous desert. Derricks, scaffolds, and pumping. gear took the places occupied by the tall forest trees or blooming orchards. Groups of warehouses, barrel factories, boarding-houses, and whole villages replaced each solitary farm-house. The stream was dammed and sluiced for artificial floods, harbors were excavated in the lowest places, and the rest of the intervale became a stinking bog of mud and salt mingled with oil. Not a blade of grass was to be secn, and nothing to be heard but the clanking of the pumps, the blowing of some new well in its first energy, the shouting of drivers urging miserable mules and horses through the nauseous mud, dragging empty barrels to the wells, or full onesdown to the stream, where the boatmen fasten them together for the next flood. Long barges filled with casks, or with the oil itself in bulk, lie waiting for the moving of the waters, when the upper dam is opened. Among them are to be seen strange crafts, composed of barrels lashed together like a raft, or barrels sawed in two and lashed together thus, to carry the oil in bulk, and filled to the brim.

Occasionally the pond freshets, as they are called, become scenes of ludicrous disaster. The latest were those of December 2 and December 5, 1862, in which fifty thousand barrels of oil were lost. “The loss on the Alleghany river,” writes a correspondent, “is estimated at 400,000 or 500,000 gallons.”  The scene is graphically described in the columns of the Philadelphia Coal Oil Circular of December 13: “The boats grounding in great numbers; the larger overriding, crushing, and swamping the smaller craft, and breaking each other up. In the Friday’s freshet twenty ill-secured boats at the upper wells broke loose when the water was first let off, and came down broad side, making a clean sweep of the creek, tearing away from the shores all the boats that lay successively below them, in spite of the frantic efforts of their owners, Oily ropes in oily hands were of no avail for snubbing round oily posts; everything went with a run, or rather with a slide, and for once, at least, the creek deserves its name. Boatmen, standing on oily thwarts and gunwales, and handling oily poles, were capsized into the water, and came out dripping with oil. One reporter counted fifty-six considerable wrecks between the Tar farm and Oil creek bridge. Boats were forced up to their full lengths out of the water upon the McClintock bridge pier, like floes of ice; three hundred barrels, staved and whole, floated from one of them alone. The new railroad will prevent such tragico-comic scenes from happening in future.”

But far more fearful scenes than these by water have occurred on shore.  More than once, in spite of all precaution, a spouting well has taken fire, and roared and burned like a volcano. Then pump works, engine-houses, stores and boats, the soil, the stream, and the river into which it pours its flame, spread their common conflagration over day and night. In the autumn of 1861 a well about three miles up Oil creek was lit by a cigar, while thirty or forty people were standing around it, of whom fifteen were killed instantly by the explosion and thirteen severely injured. A column of fire, with its head rising and falling from thirty to fifty feet, continued to burn.

The Little & Merrick well was one hundred and fifty feet deep at first, but in the spring of 1861 was deepened, without considerable increase of oil, until half-past six o’clock in the afternoon of April 17, when, from a depth of three hundred and thirty feet, a stream of oil and gas, mixed with a very little water, four inches in diameter, rushed up with such violence that its spray reached far beyond the top of the derrick. The air became an atmosphere of gas. The sickened hands forsook their boring tools and fled, leaving the oil to waste itself, like a cataract, into the creek. The engine firemen put their fires out. Soon a great crowd collected from the older works, and closely surrounded the new jet, when, suddenly, two simultaneous flashes, and a report like the rolling fire of a platoon of musketry, as it seemed to those at hand, but like two separate cannon shots to those who felt the concussions three miles distant, and to those that heard them seven and eight miles off, inaugurated a general conflagration. A scene of indescribable terror and confusion ensued.  Yet all escaped but half a dozen, who were burned to charcoal where they stood; many others died, however, of their wounds, and numbers more were scarred for life. Four wells lost everything, including 500 barrels of oil on hand, and other property was destroyed elsewhere, In the dead of night there stood the fountain of flame, a jet of pure oil, not subsiding and returning to its work, but a ceaseless, unintermittent rush, like the steady blowing off of a steam boiler, and more than a hundred feet in height, rolling clouds of black and massive smoke up over the tops of the surrounding hills with a ceaseless, surf-like roar.

In the autumn of 1862 the tanks of the Filkins well caught fire, and the space burned over soon embraced from eighteen to twenty acres, on which one hundred and fifty oil tanks, full of a three months’ supply, were standing close together, intermingled with engine-houses, offices, &c. Seven flowing and three pumping wells, with thirty thousand barrels of oil, took fire in quick succession. The flames ran up the trees of the maple grove, and the valley was black with smoke that stifled the heroic men who fought the flames. Men stood bravely on tanks of oil as dangerous as so many powder magazines.  Oil creek, of course, took fire, and increased the grandeur of the scene. There were no explosions during the whole conflagration; crude oil is not explosive.

Total number of refiners, 25; amount of daily flow of oil, 6,717 barrels; amount at date on hand, 92,450 barrels; amount already shipped, about 1,000,000 barrels; valued at about $1,092,060 on the ground. Average cost of a well, $1,000; of all the wells, $495,000; machinery, &c., $500 to $7,000; of all the wells, $500,000.

But the oil region extended much further north. A citizen of Cuba, Alleghany county, New York, writes, under date of J: anuary 3, 1861: “Qur village to-day is in a blaze of excitement, consequent upon the discovery of oil in large quantities in this immediate vicinity.” An old mud hole, twenty feet across and ten feet deep, exists at the foot of the hill on the west side of the village, always covered with oil, famous for curing sprains and bruises. It is included in an Indian reservation one mile square, and has been described in the history of Sullivan’s campaign. Governor Seymour, Judge Chamberlain, and others took possession of the reservation a few years ago, and have carried on lawsuits with the Indian claimants ever since; but in 1860 Alden, Bradley & Co. leased it of all parties, and began to drive a pipe down into the bog. At thirty feet the oil began to spout at the rate of a barrel an hour; other wells soon followed. Thus one oil field after another was opened and occupied in the United States along the western borders of the great coal field.

Meanwhile the western Canadians were not idle.  The existence of bitumen in the corniferous limestone formation of the peninsula had been reported to the chief of the geological survey of the province by Mr. Murray, the western assistant geologist, as early as 1844, and the oil springs of the valleys of the Thames river and Bear creek are to be seen described in the reports of progress of 1850 and 1851. In 1853 the process of Mr. Young, of Glasgow, brought these Enniskillen county bitumen springs into wide repute, and in 1857 Mr. William M. Williams, of Hamilton, quitted the distillation of the solid bitumen, to undertake deep borings, in the hope of reaching its mother oil in larger quantities. Although in far lower formation than those from which the United States oil proceeds, he was entirely successful, and was followed by a crowd of adventurers, who sank nearly a hundred wells in Black and Bear Creek valleys before the visit of Mr. T. Sterry Hunt, in December, 1860.  By his report we learn that from the small proportion of this number that did produce available quantities there had, nevertheless, been obtained at least 300,000 gallons.  Since then others have been finished. In August, 1862, there were three hundred, and three new and productive wells were reported in November following. Even at Gaspé, near the mouth of the St. Lawrence, where Sir William Gogan describes petroleum springs long ago, companies began to be formed in 1861 to bore for oil.

In Virginia wells are in operation in Ritchie and Wirt counties.

It is probable that all instances of solid bitumen found on or beneath the urface of the earth have resulted from the hardening of drops or reservoirs of liquid coal oil. The lumps and crystals of graphite found in the oldest rocks, like the lumps of amber found in the newest, were doubtless oily substances involved by sand and mud. Flakes of anthracite are found in the centre of rock crystal. Gelatinous animals and fucous plants abounded in these ancient seas, and ought to have provided, by their death, plenty of animal and vegetable hydrocarbon for the mineral. The old red sandstones, like more modern formations, present us, for our cabinets, innumerable flattened fish, converted into bitumen; some in so perfect a state that every scale can be counted, and every sculptured line upon them submitted separately to the microscope; others an undistinguishable mass or daub of tar. Some rocks have been so thoroughly charged with animal dead matter that they emit a fetid odor whenever struck, and are technically known as stinkstones. The bituminous limestones and shales of many different geological ages are so many reservoirs of animal and vegetable oil, produced by the death and slow decomposition of successive floral and faunal creations, perhaps principally coralline. The fossiliferous black shales of the central belt of the State of New York underlie Lake Erie, cross Ohio and Kentucky into Tennessee, and return through Indiana and form the beds of Lakes Michigan and Huron. In middle Kentucky the faces of the rocks are smeared and streaked with oil, fried out of them by the sun, so that the surfaces are blackened as if with tar.

Up to the horizon of these black slates, ascending in the column of deposits, gelatinous sea organisms, both animal and vegetable, seem to have constituted the principal, if not the sole, apparatus for generating petroleum. But Dawson has lately discovered in the sandstones over them a true angiospermous exogenous tree, not much, if any, lower in the scale of development than those of which our forests are composed. Coniferous trees began also to abound, and coal beds to be deposited in groups. Thence the higher we ascend towards and through the second and the third or great coal measures, the more abundant became the vestiges of fresh water and land vegetation, until in the tree stumps of the coal beds of Nova Scotia we find small land animals. The mosses and ferns, the rushes and reeds, minute and gigantic, of which the coal beds came, suggest the vegetable origin of coal oil. For it is near or between the three systems of coal measures which succeed each other in ascending from the top of the upper silurian to the coal measures proper that the amazing discoveries of subterranean reservoirs of oil had taken place. It is impossible to suppress the suspicion that petroleum is a product of the slow decomposition of vegetable tissue.

But the oil wells are not sunk in coal measures, but through them at the edge of the great coal area. The oil is never found in coal beds; nor have the subterranean reservoirs of oil apparently any connexion with coal beds, nor even with coal slates, or bituminous shales or pyroschists, as they are called. Black: slate, cannel, fat coal, like lignite, peat and living wood, will yield the oils and gases by distillation, but the geological distinetion must be carefully preserved between the free petroleum of the rocks and wells and the distilled petroleum of the old oil works.

The connexion of the oil regions with the coal basins of western Pennsylvania and Virginia, eastern Ohio and Kentucky, is, in good measure, a geographical deception.*³ The Oil creek rocks, dipping southward, pass 500 or 600 feet below the coal measures. The nearest coal bed to the more northern springs occurs on the highest hill-tops, many miles away. The hills in the vicinity of some of the wells are capped by the conglomerate base of the coal measures at least a hundred feet thick. The shales and sandstones of the valley belong to formations X, IX, and VIII descending, called by the New York geologist the Catskill, Chemung, and Portage groups, extending over all the southern counties of western New York. The southern dip carries down these oil-bearing rocks, and the wells must deepen in the same direction. Mr. Ridgeway reports (July 10, 1862) the lowest oil-bearing sand rock, as capping the hills near Waterford, on Le Bœuff creek, and the same sandstones appear on Big French creek, full of plant remains.

The following wells show the dip in a well-marked manner: The Phillipps well, on Oil creek, is 460 feet; the Brawley well, at the mouth of Cherry run, 503 feet; the Cornwall well, 530 feet; the Avery well, over 700 feet; and at Titusville he estimates the proper depth at 1,000 or 1,200 feet.

In the Mahoning coal oil region in western Pennsylvania and eastern Ohio, near the line, the three oil-bearing sand rock strata are beneath the lowest coal bed. The "Continental” boring at Edenburg, in Lawrence county, penetrated, in descending order, the following formations before it struck the oil.  First, the superficial drift, 80 feet thick. Second, sandstones and shales, 200 feet thick, the bottom layers of which consisted of fetid black shales, from which coal gas blew off with violence. Third, the first white sandstone, 50 feet thick, arranged in three strata, a softer middle between harder upper and lower formations; the whole mass said to be thin, going east, and holding abundance of gas in its crevices. Fourth, shales and slates, 45 feet thick, charged with oil and gas.  Fifth, the second white sandstone, 75 feet thick— softer, coarser, and tougher, or more difficult to bore through than the first, and full of gas; after passing through which they struck the great oil stratum, 448 feet from the surface. Crawford’s boring, not far off, went down 580 feet, through another shaley formation, and struck oil, supposed to come up through a crevice from the third white sand rock.

That there is an intimate connexion between the character of these sand formations and the character of the oil which issues from them is indubitable.  The rule among the miners is, as stated by Mr. Clark in the "Proceedings of the American Philosophical Society,” (June, 1862, page 57,) that the harder the rock may be to drill, the lighter in color, purer in quality, and smaller in quantity, will be the oil obtained therefrom; and the softer the rock, the darker and more abundant the oil.

The chemist of the Canada survey, Mr. Hunt, insists strenuously “upon the distinction between lignitic and bituminous rocks, inasmuch as some have been disposed” he says, “to regard the former as the source of the bitumen found in nature, which they conceive to have originated from a slow distillation. The result of a careful examination of the question has, however, led us to the conclusion that the formation of the one excludes more or less completely that of the other, and that bitumen has been generated under conditions different from those which have transformed organic matters into coal and lignite; and probably, in deep-water deposits, from which atmospheric oxygen was excluded.”

Mr. Hunt instances in support of this view, the fact that the highly inflammable pyroschists or black slates of the Utica and Hamilton groups contain no soluble bitumen, and that the Trenton and corniferous limestones at the base of the silurian system are impregnated with petroleum, and give rise to petroleum springs, although no fossil land plant has been found in them. The fact that a considerable portion of the tissues of the lower marine animals is destitute of nitrogen, am%1 very similar in chemical composition to the woody fibre of plants, forms another link in the chain of reasoning on this distinction between bituminuous and lignitic rocks. The black slates, and even the coal beds are, in fact, layers of mud, charged slightly or to excess with lignitic matter, peat, or humus, part of which has assumed the form of glance coal and part the form of mineral charcoal, but almost none of which is soluble in benzole or sulphuret of carbon; whereas these liquids easily dissolve out the ready-formed bitumen from the rocks which may contain them. But whenever a coal bed became a repository of dead fish, like the eight-foot coal at the mouth of Yellow creek, at the bend of the Ohio, or as in the case of the two-foot stratum of phosphatic iron-ore deposited between the two benches of the Deep River coal-bed, at Egypt, in North Carolina—how different an aspect the mineral then wears, glossy with soluble bitumen!

Mr. Hunt argues with much force that the mere fact that intermediate strata, porous enough to absorb all the floating bitumen in their vicinity, are nevertheless destitute of any, is enough to prove that the accumulations of oil now furnishing the world with light, never came from the sub-volcanic distillations of the beds of coal in their neighborhood, but that the mineral has been generated by the transformation of organic matter in the strata where it is. Mr. Wall has shown that the asphalt of Trinidad and Venezuela (belonging however to a much later—upper miocene or lower pliocene—tertiary age) occurs in limestones, sandstones, and shales, associated with beds of lignite or fossil wood, and is confined to particular strata which were originally shales containing vegetable remains which have undergone “a special mineralization, producing a bituminous matter instead of coal or lignite, and not attributable to heat, nor of the nature of a distillation, but due to chemical reaction at the ordinary temperature and under the normal conditions of climate.” He describes, also, wood partially converted into bitumen, when removed by solution, woody fibre remains.—(Proc. Geol. Soc., Lond., May 1860. Hunt.)

The theory of the genesis of coal oil is, however, far from being cleared up by such facts.  It is true that the oil is not found in immediate contact with coal beds made of land or fresh-water plants; but on the other hand, coal oil regions are geographically connected with coal-bed regions, whether of devonian, carboniferous, oolitic, or tertiary age. Coal beds are said to underlie the Rangoon oil wells. Tertiary lignites abound in Trinidad, Venezuela, Lombardy, and middle Asia. The lower devonian horizon of the Canada black-slate oil region yields coal beds in Pennsylvania. The structural difficulties attending the solution of the problem remain.

Fissures are filled with oil, and gas, and salt water, and different wells strike them at different depths. The oil-bearing sand rocks seem charged from top to bottom with gas and blow off from every fissure as it is passed through by the auger. Whence comes this gas, if not by subterranean distillation? It is impossible to postulate the gas first and the oil afterwards; for that order would require the generation of pressure sufficient afterwards, and the oil would be in the condition of a mechanically explosible fluid. The gas must be a subsequent expansion of the oil, as it is in the case of coal-mine fire-damp.  Whence, then, comes the oil, and why has it collected in reservoirs? How are guch reservoirs preserved, and what is their extent? It is easy, after these questions have been answered, to describe the mechanical propulsion of the oil to the surface, partly by gravity and partly by the pressure gf the gas it has itself generated, through natural fissures producing natural oil springs, or through artificial auger holes.  The intermittent action of most of the flowing and spouting wells is like that of the Iceland geysers, where steam is the motive power. The oil men of the Mahoning valley say that more gas is blown off in winter than in summer.

At the Edenburg well, above referred to, the blast of gas is sometimes violent enough to stop the pumping engine for half an hour at a time. Mr. Clark reports a periodicity or daily maximum in the paroxysms. He noticed for several weeks that they recurred with singular regularity a few minutes after eight o’clock in the evening, when the engine was forced to stop for twenty minutes or half an hour.

In the almost unchanged horizontal posture of the western coal measures no considerable fracturing or fissuring took place. Faults of all kinds are uncommon and very small when they exist at all. The rise of the stratification from the Alleghany river towards Lake Erie is a fraction of one degree. The original contents of the rocks have therefore been preserved. Not so with the anthracite basins on the southeastern side of the great coal area. Crushed and upturned and overturned, contorted and fractured in every part, this part of the earth’s crust has been dried and hardened, and exposed to chemical action from the superincumbent drainage waters, until its various formations (the coal beds included in the number) have been metamorphosed and partially recrystallized. The oils which they contained have been lost by dissolution and evaporation. The bituminous coals have become anthracites, and the last oil spring on the headwaters of the Lehigh, the Schuylkill, the Juniata, the Potomac, or the New river, ceased to flow many millions of years ago. In the west, on the contrary, in equally ancient, nay, in identically the same rocks, the petroleum still remains, having had no outlet; always hermetically sealed and under pressure. It remains partly condensed in coal beds and black shales, partly distributed through the sand rocks and limestones, and partly filling up the joints which the shrinking of ages has produced. Possibly a small portion of it may be held in caverns through the more soluble limestone strata. Especially important are the water-bearing horizons.

The vertical cleavage planes and few down-throw fissures which exist play but a subordinate role to these. Rain-waters percolate from every hill surface and valley bed, sidewise and downwards, leeching every permeable stratum that will give up its salt and oily contents. Along the outcrops of every coal bed issue innumerable springs of painted water. At the base of every great sand rock, and on the top of the clayey deposits next below it, collect the mixed proceeds of the drainage in a standing sheet of oily brine. Capillary attraction and hydrostatic pressure perpetually re-enforce the reservoir. The weight of rock on top and the pressure of disengaged oil-gas sends its filaments forward and upward by every secret crack to the surface again, holding it in every part ready for an explosive rush into the air when an artificial outlet is provided. If there be no fissure in the locality, the oil wells descend to the sheet of water at about the same depth. Where fissures intercept them they are of various depths and fortune, for a well may pass a fissure where its walls are polished and tight together. A well may also pass the water sheet where some change in the porosity of the rocks above and below has taken place to oppose a like obstruction. In some parts of the western coal-field the dip is as high as five degrees, and the basins from five to ten miles wide. Sharp flexures make local dips of thirty degrees or more, and a central sub-anticlinal is sure to subdivide the basin. In the secondary basins thus formed the wells are more perfectly artesian as to the salt water; but it is upon the subdividing anticlinals that the gas and oil collect. In such regions if is asserted that all the blowing and many of the spouting wells are ranged along the summits of such anticlinals. In the case of some of the old gas-blowing salt-wells, their actions demonstrate that they have been bored past one gas-bearing stratum to another deeper salt water stratum; for when the water is allowed rise in the auger hole, by stopping the pumps awhile, then the gas and oil no longer come up, the brine stopping their issue. In the case of neighboring wells of different depths striking a slanting fissure, the one which strikes it highest up will deliver gas; another, striking it lower down, will deliver oil; a third, striking it still lower down, will deliver nothing but salt water.

The compressibility of coal-oil gas is one of its most dangerous qualities, increasing indefinitely the dangers of those explosions which annually cost so many valuable lives. Confined in the walls of the gangways and rooms, it issues from innumerable cells or pockets, the larger of which are called "blowers;” sometimes with the noise of heavy rain; sometimes with small reports.  It collects among the timbers of the roof, in the upper galleries of the mine, in deserted portions of the colliery, and especially in those accumulations of refuse coal and slate, called “gob,” or "goaf,” with which the miners pillar up the superincumbent rocks. These acres of worked-out and filled-up galleries become vast reservoirs of fire-damp. The gas collects especially over the anticlinal rolls. From these great powder magazines, solicited by the least diminution of barometric pressure in the atmosphere, the gas rushes out to fill the working rooms. Long experience has shown that a falling barometer and explosions in coal mines always go together. But the mischief is accumulative.  The vacuum produced by the first explosion is a new provocation to the world of back gas to leave its hiding places, come forward afresh, and produce another, and again another, until the proportion of air to gas becomes too small to make an explosive mixture; so that, like the stroke of lightning, the coal mine explosion is not a unit, but a series, cause and effect reciprocally acting to produce the last result.

Among the most curious: exhibitions of superior lightness of petroleum to other minerals with which it is found, and of the nice train of reasoning dependent thereon, is the observation of Mr. Vanuxem that the film of black bitumen found in the cavities of the calciferous sand rock of New York, with crystals of bitter spar and quartz, occur on the upper side of the crystals, on the mother liquor of which they once floated as pellicles of oil; and, as the crystal hardened and grew, it moulded the oxydated oil to a sheet of bitumen, brittle, very pulverulent, of a shiny black, yielding little ash, and 11½ per cent. of (principally) water. The same mamillary surface, arguing original fluidity, characterizes the specimens obtained by the Canadian mineralogist from the Quebec group—filling cavities in its limestones, sandstones, and even in the accompanying trap dykes; readily crumbling to a black powder, and, when highly heated, giving off an abundance of strong-smelling, inflammable gas, condensing to a tarry oil, and leaving 80 per cent. of a black residue, which, when heated slowly, burns away, leaving only a trace of ash. The same kind of mineral found at the Acton copper mine is harder, less friable, and more like anthracite—(Hunt.) The petroleum which fills cavities in the Montmorencie rocks is still unhardened. It flows in drops from a fossil coral of the Birdseye limestone there; and at Pakenham it fills the cast moulds of large orthoceratites in the Trenton limestone to such an extent that about a pint has been poured out of one. Tt is perhaps from these lower silurian fossil coralline limestones that the oil makes its way to the surface through the overlying Loraine shales to form the Guilderland oil spring near Albany, according to Beck, through the Utica slate on the Great Manitoulin island, and through the red Medina shales at Albion mills, near Hamilton, according to Mr. Murray.—(Hunt.)

The next great limestone in the ascending series is the Niagara, and Eaton early made known the oozing of petroleum from its fossil casts. Hall describes it in Monroe county as a granular crystalline dolomite, including small laminæ of bitumen, which give it a resinous lustre. Bitumen sometimes flows like tar from the lime-kiln. The corniferous limestone, next above the Niagara, has the cells of its fossil corals filled with petroleum, the remains of the gelatinous coral animal which inhabited them. Mr. Murray drew attention to this fact in 1844, and cited the Gravelly bay quarries in Wainfleet, Western Canada, as examples.—(Report of 1846.)

The oil springs of Enniskillen, as well as the lake of solid bitumen in the same township, half an acre in extent and two feet thick, no deubt have their deep-seated sources not in the black shales of the region, but in the corniferous limestone underneath. These black shales belong to the base of the Portage and Chemung group. The wells sunk in them soon strike the argillaceous shales and limestones of the Hamilton group, and go through them toward the coniferous limestone, specimens of which yielded to Hunt’s analysis from 7.4 to 12.8 per cent. of bitumen, fusible and readily soluble in benzole.

In the blackish Marcellus shales, at the base of the Hamilton group, are found septaria or nodular concretions containing petroleum. The same phenomenon recurs at the top of the Hamilton group. Still higher up, the Portage: and Chemung sandstones (formation viii;) are often bituminous to the smell, and contain petroleum in cavities; or hardened into solid seams. A calcareous sand rock in Chatauqua county contains more than 2 per cent. of bituminous matter. These are the rocks around the famous oil springs of the Seneca Indians. It is only necessary to ascend the series of these devonian sandstones to their upper part among the rocks of the Catskill group, or just beneath them, to find oneself in: the oil regions of northern Pennsylvania and Ohio, described by Dr. Newberry and others; and sufficiently treated of in the foregoing pages.

There only remains to be noticed that anomalous deposit of the Albert coal in New Brunswick, made famous by long litigation and the discussion of geologists, described by Professor Dawson in his Acadian Geology, and called by Dr. Wetherill, of Philadelphia, Melan-asphalt.—(Trans. Amer. Phil. Soc., July 16, 1852.)

Its position has been misinterpreted by several observers, who have reported it a volcanic injection of bitumen into a fissure of the earth, many feet in width, by the force of which large pieces of the wall rock have been torn off and carried forward in the mass. It seems, however, pretty well made out, that it was originally a horizontal bed or lake of petroleum, hardened and covered up by sand and clay deposits of carboniferous age, and afterwards upturned, bent over and fractured so as to assume its present posture. It is not properly a coal bed, therefore, but a mass of hardened coil oil, which can be, and, in fact, has been, mined like a coal bed, and the product used wholly for making gas.  Dr. Wetherill’s analysis gives: Coke, 44.35; volatile matter, 55.55; ash, 0.10. Specimens of Cuban asphalt analyzed at the same time gave: Coke, 32.00; volatile matter, 67.60; ash, 0.40; or, subtracting the ash and uniting the oxygen and nitrogen: Carbon, 86.123; hydrogen, 8.971; oxygen and hydrogen, 4.906 = C⁶⁸ H⁴² O N. Like Cuban and Egyptian asphalt, this Albertine (as it is commonly called) is highly electrified by friction, which coal is not.

1. M. Tournet has lately demonstrated that the brilliant colors of gems, such as the emerald, aqua-marina, and amethyst, are due to the diffused presence of hydrocarbons.  They are, in fact, a natural production of the aniline colors in coal tar, and not, as once thought, metallic lustres.
2. The Stephenson House, St. Catharine’s, burns 180 flames for 86 cents per night.—( Phil. Coal Oil Circular, December 6, 1862, 1st page. Full discussion.)
3. In the report of a geological reconnoissance of Indiana, 1859, 1860, under D. D. Owen, State geologist, and published in 1862, Professor Lesquereux expressed the opinion that the mineral oil of the borders of the coal field comes from the lowest great bed of the coal measures, I. B., (page 285.) The opinion of such an authority is to be carefully considered.