Chapter 2

On the other hand it is to be specially noticed that, with a few unimportant exceptions, all bituminous deposits are found in the sedimentary rocks, and that just as these are constantly changing in composition, so the organic matter present changes, there being a definite relationship between the chemical constitution of the petroleum and the age of the strata in which it is found. It is almost certain that in the most recent alluvial formations no oil is ever found, its latest appearance being in the rocks of the tertiary period, the place where the solid paraffin is almost exclusively met with; thus helping to show that the latter has been formed from the decomposition of the oil, and is not a residue remaining after the oil has been distilled off. To this conclusion the fact also strongly points, that the paraffin is much simpler in constitution, purer, and often of far lighter color than the crude oil, which could not be the case if it were the original substance.

On examining by the aid of a map the position of the chief oil-bearing localities it will be noticed that the most prolific spots follow fairly accurately the contour lines of the country, so that at one time they formed in all probability a coast line whereon would be concentrated for climatic reasons most of the animal life both of the land and sea. During succeeding generations their dead bodies would accumulate in enormous quantities and be buried in the slowly depositing sand and mud, till, owing to the gradual alterations of level, the sea no longer reached the same point. This theory is borne out by the fact that oil deposits are usually found in marine sediments, sea fossils being frequently met with. The first process of the decomposition of the animal remains would consist in the formation of ammonia and nitrogenous bases, the action being aided by the presence of air, moisture, and micro-organisms, at the same time, owing to the well known antiseptic properties of salt, the decomposition would go on slowly, allowing time for more sand and inorganic matter to be deposited. In this way the decomposing matter would be gradually protected from the action of the air, and finally the various fatty substances would be found mixed with large amounts of salt, under considerable pressure, and at a somewhat high temperature. From this adipocere, fatty acids would be gradually formed, the glycerol being washed away, and finally the acids would be decomposed by the pressure into hydrocarbons and free carbonic acid gas. That many of these hydrocarbons would be solid at ordinary temperatures, forming the so-called mineral wax, which exists in many places in large quantities, is much easier to imagine, in the light of modern chemical knowledge, than that the fatty acids were at once split up into the simpler liquid hydrocarbons, to be afterward condensed into the more complex molecular forms of the solid substance.

In this way from animal matter are in all probability formed the vast petroleum deposits, the three substances, adipocere, ozokerite, and petroleum oil being produced in chronological order, just as lignite, brown coal and coal are formed by the gradual decomposition of vegetable remains.

* * * * *

THE ORIGIN OF PETROLEUM.[1]

[Footnote 1: Abstract of a paper read before the British Association, Cardiff meeting, 1891, Section G.]

By O.C.D. Ross, M.Inst.C.E.

Petroleum is one of the most widely distributed substances in nature, but the question how it was originally produced has never yet been satisfactorily determined, and continues a problem for philosophers. In 1889 the total production exceeded 2,600,000,000 gallons, or about 10,000,000 tons, and, at fourpence per gallon, was worth about £44,000,000, while the recognition of its superior utility as an economical source of light, heat, and power steadily increases; but, notwithstanding its importance in industry, the increasing abundance of the foreign supply, and the ever-widening area of production, practical men in England continue to distrust its permanence, and owing to the mystery surrounding its origin, and the paucity of indications where and how to undertake the boring of wells, they hesitate to seek for it in this country, or even to extend the use of it whenever that would involve alterations of existing machinery. The object of this paper is to suggest an explanation of the mystery which seems calculated to dissipate that distrust, since it points to very abundant stores, both native and foreign, yet undiscovered, and even in some localities to daily renovated provisions of this remarkable oil.

The theories of its origin suggested by Reichenbach, Berthelot, Mendeleeff, Peckham, and others, made no attempt to account for the exceeding variety in its chemical composition, in its specific gravity, its boiling points, etc., and are all founded on some hypothetical process which differs from any with which we are acquainted; but modern geologists are agreed that, as a rule, the records of the earth's history should be read in accordance with those laws of nature which continue in force at the present day, e.g., the decomposition of fish and cetaceous animals could not now produce oil containing paraffin. Hence we can hardly believe it was possible thousands or millions of years ago, if it can be proved that any of the processes of nature with which we are familiar is calculated to produce it.

The chief characteristics of petroleum strata are enumerated as:

I. The existence of adjoining beds of limestone, gypsum, etc.

II. The evidence of volcanic action in close proximity to them.

III. The presence of salt water in the wells.

I. All writers have noticed the presence of limestone close to petroleum fields in the United States and Canada, in the Caucasus, in Burma, etc., but they have been most impressed by its being "fossiliferous," or shell limestone, and have drawn the erroneous inference that the animal matter once contained in those shells originated petroleum; but no fish oil ever contained paraffin. On the other hand, the fossil shells are carbonate of lime, and, as such, capable of producing petroleum under conditions such as many limestone beds have been subjected to in all ages of the earth's history. All limestone rocks were formed under water, and are mainly composed of calcareous shells, corals, encrinites, and foraminfera--the latter similar to the foraminfera of "Atlantic ooze" and of English chalk beds. Everywhere, under the microscope, the original connection of limestone with organic matter--its organic parentage, so to speak, and cousinship with the animal and vegetable kingdoms--is conspicuous. When pure it contains 12 per cent. of carbon.

Now petroleum consists largely of carbon, its average composition being 85 per cent. of carbon and 15 per cent. of hydrogen, and in the limestone rocks of the United Kingdom alone there is a far larger accumulation of carbon than in all the coal measures the world contains. A range of limestone rock 100 miles in length by 10 miles in width, and 1,000 yards in depth, would contain 743,000 million tons of carbon, or sufficient to provide carbon for 875,000 million tons of petroleum. Deposits of oil-bearing shale have also limestone close at hand; e.g., coral rag underlies Kimmeridge clay, as it also underlies the famous black shale in Kentucky, which is extraordinarily rich in oil.

II. As evidence of volcanic action in close proximity to petroleum strata, the mud volcanoes at Baku and in Burma are described, and a sulphur mine in Spain is mentioned (with which the writer is well acquainted), situated near an extinct volcano, where a perpetual gas flame in a neighboring chapel and other symptoms indicate that petroleum is not far off. While engaged in studying the geological conditions of this mine, the author observed that Dr. Christoff Bischoff records in his writings that he had produced sulphur in his own laboratory by passing hot volcanic gases through chalk, which, when expressed in a chemical formula, leads at once to the postulate that, in addition to sulphur, _ethylene_, and all its homologues (C_{n}H_{2n}), which are the oils predominating at Baku, would be produced by treating:

2, 3, 4, 5 equivs. of carbonate of lime (limestone) with 2, 3, 4, 5 " sulphurous acid (SO_{2}) and 4, 6, 8, 10 " sulphureted hydrogen (H_{2}S);

and that marsh gas and its homologues, which are the oils predominating in Pennsylvania, would be produced by treating:

1, 2, 3, 4, 5 equivs. of carbonate of lime with 1, 2, 3, 4, 5 " sulphurous acid and 3, 5, 7, 9, 11 " sulphureted hydrogen.

Thus we find that:

Carbonate of lime, 2CaCO_{3}, } { 2(CaSO.H_{2}O) (gypsum), Sulphurous acid, 2SO_{2}, and } yield { 4S (sulphur), and Sulphureted hydrogen, 4H_{2}S, } { C_{2}H_{4}, which is { _ethylene_.

And that:

Carbonate of lime, CaCO_{3} } { (CaSO_{4}.H_{2}O) (gypsum), Sulphurous acid, SO_{2}, and } yield { 3S (sulphur) and Sulphureted hydrogen, 3H_{2}S, } { CH4, which is marsh gas.

So that these and all their homologues, in fact petroleum in all its varieties, would be produced in nature by the action of volcanic gases on limestone.

But much the most abundant of the volcanic gases appear at the surface as steam, and petroleum seems to have been more usually produced without sulphurous acid, and with part of the sulphureted hydrogen (H_{2}S) replaced by H_{2}O (steam) or H_{2}O_{2} (peroxide of hydrogen), which is the product that results from the combination of sulphureted hydrogen and sulphurous acid:

(H_{2}S + SO_{2} == H_{2}O_{2} + 2S).

It is a powerful oxidizing agent, and it converts sulphurous into sulphuric acid. Thus:

CaCO_{3} } { CaSO_{4}.H_{2}O (gypsum) H_{2}S, } yield { and 2H_{2}O, } { CH_{4}, which is marsh gas.

And

2CaCO_{3}, } { 2CaSO_{4}.H_{2}O 2H_{2}S, } yield { and 2H_{2}O_{2}, } { C_{2}H_{4}, which is _ethylene._

Tables are given showing the formulæ for the homologues of ethylene and marsh gas resulting from the increase in regular gradation of the same constituents.

_Formulæ Showing how Ethylene and its Homologues (C_{n}H_{2}{n}) are Produced by the Action of the Volcanic Gases H_{2}S and H_{2}O_{2} on Limestone._

Carbonate Sulphureted Peroxide of Ethylene and of lime. hydrogen. hydrogen. Gypsum. its homologues.

2CaCO3 + 2H2S + 2H2O2 yield 2(CaSO4.H2O) + C2H4 ethylene (gaseous). 3CaCO3 + 3H2S + 3H2O2 " 3(CaSO4.H2O) + C3H6 4CaCO3 + 4H2S + 4H2O2 " 4(CaSO4.H2O) + C4H8 5CaCO3 + 5H2S + 5H2O2 " 5(CaSO4.H2O) + C5H10 6CaCO3 + 6H2S + 6H2O2 " 6(CaSO4.H2O) + C6H12 Boiling point. 7CaCO3 + 7H2S + 7H2O2 " 7(CaSO4.H2O) + C7H14 -- 8CaCO3 + 8H2S + 8H2O2 " 8(CaSO4.H2O) + C8H16 189°C. 9CaCO3 + 9H2S + 9H2O2 " 9(CaSO4.H2O) + C9H18 136°C. 10CaCO3 + 10H2S + 10H2O2 " 10(CaSO4.H2O) + C10H20 160°C. 11CaCO3 + 11H2S + 11H2O2 " 11(CaSO4.H2O) + C11H22 180°C. 12CaCO3 + 12H2S + 12H2O2 " 12(CaSO4.H2O) + C12H24 196°C. 13CaCO3 + 13H2S + 13H2O2 " 13(CaSO4.H2O) + C13H26 240°C. 14CaCO3 + 14H2S + 14H2O2 " 14(CaSO4.H2O) + C14H28 247°C. 15CaCO3 + 15H2S + 15H2O2 " 15(CaSO4.H2O) + C15H30 --

It is explained that these effects must have occurred, not at periods of acute volcanic eruptions, but in conditions which maybe, and have been, observed at the present time, wherever there are active solfataras or mud volcanoes at work. Descriptions of the action of solfataras by the late Sir Richard Burton and by a British consul in Iceland are quoted, and also a paragraph from Lyall's "Principles of Geology," in which he remarks of the mud volcanoes at Girgenti (Sicily) that _carbureted hydrogen_ is discharged from them, sometimes with great violence, and that they are known to have been casting out water, mixed with mud and _bitumen_, with the same activity as now for the last fifteen centuries. Probably at all these solfataras, if the gases traverse limestone, fresh deposits of oil-bearing strata are accumulating, and the same volcanic action has been occurring during many successive geological periods and millions of years; so that it is difficult to conceive limits to the magnitude of the stores of petroleum which may be awaiting discovery in the subterranean depths.[2]

[Footnote 2: Professor J. Le Conte, when presiding recently at the International Geological Congress at Washington, mentioned that in the United States extensive lava floods have been observed, covering areas from 10,000 to 100,000 square miles in extent and from 2,000 to 4,000 feet deep. We have similar lava flows and ashes in the North of England, in Scotland, and in Ireland, varying from 3,000 to 6,000 feet in depth. In the Lake District they are nearly 12,000 feet deep. Solfataras are active during the intermediate, or so-called "dormant," periods which occur between acute volcanic eruptions.]

Gypsum may also be an indication of oil-bearing strata, for the substitution in limestone of sulphuric for carbonic acid can only be accounted for by the action of these hot sulphurous gases. Gypsum is found extensively in the petroleum districts of the United States, and it underlies the rock salt beds at Middlesboro, where, on being pierced, it has given passage to oil gas, which issues abundantly, mixed with brine, from a great depth.

III. Besides the space occupied by "natural gas," which is very extensive, 17,000 million gallons of petroleum have been raised in America since 1860, and that quantity must have occupied more than 100,000,000 cubic yards, a space equal to a subterranean cavern 100 yards wide by 20 feet deep, and 82 miles in length, and it is suggested that beds of "porous sandstone" could hardly have contained so much; while vast receptacles may exist, carved by volcanic water out of former beds of rock salt adjoining the limestone, which would account for the brine that usually accompanies petroleum. It is further suggested that when no such vacant spaces were available, the hydrocarbon vapors would be absorbed into, and condensed in, contiguous clays and shales, and perhaps also in beds of coal, only partially consolidated at the time.

There is an extensive bituminous limestone formation in Persia, containing 20 per cent. of bitumen, and the theory elaborated in the paper would account for bitumen and oil having been found in Canada and Tennessee embedded in limestone, which fact is cited by Mr. Peckham as favoring his belief that some petroleums are a "product of the decomposition of animal remains."

Above all, this theory accounts for the many varieties in the chemical composition of paraffin oils in accordance with ordinary operations of nature during successive geological periods.--_Chem. News._

* * * * *

THE COLORADO DESERT LAKE.

Mr. J.J. Mcgillivray, who has been for many years in the United States mineral survey service, has some interesting things to say about the overflow of the Colorado desert, which has excited so much comment, and about which so many different stories have been told:

"None of the papers, so far as I know," said Mr. McGillivray, "have described with much accuracy or detail the interesting thing which has happened in the Colorado desert or have stated how it happened. The Colorado desert lies a short distance northwest of the upper end of the Gulf of California, and contains not far from 2,500 square miles. The Colorado River, which has now flooded it, has been flowing along to the east of it, emptying into the Gulf of California. The surface of the desert is almost all level and low, some of it below the sea level. Some few hundreds of years ago it was a bay making in from the Gulf of California, and then served as the outlet of the Colorado River. But the river carried a good deal of sediment, and in time made a bar, which slowly and surely shut off the sea on the south, leaving only a narrow channel for the escape of the river, which cut its way out, probably at some time when it was not carrying much sediment. Then the current became more rapid and cut its way back into the land, and, in doing this, did not necessarily choose the lowest place, but rather the place where the formation of the land was soft and easily cut away by the action of the water.

"While the river was cutting its way back it was, of course, carrying more or less sediment, and this was left along the banks, building them all the time higher, and confining the river more securely in its bounds. That is the Colorado River as we have known it ever since its discovery. Meantime, the water left in the shallow lake, cut off from the flow of the river, gradually evaporated--a thing that would take but a few years in that country, where the heat is intense and the humidity very low. That left somewhere about 2,000 miles of desert land, covered with a deposit of salt from the sea water which had evaporated, and most of it below the level of the sea. That is the Colorado desert as it has been known since its discovery.

"Then, last spring, came the overflow which has brought about the present state of affairs. The river was high and carrying an enormous amount of sediment in proportion to the quantity of water. This gradually filled up the bed of the stream and caused it to overflow its banks, breaking through into the dry lake where it had formerly flowed. The fact that the water is salt, which excited much comment at the time the overflow was first discovered, is, of course, due to the fact that the salt in the sea water which evaporated hundreds of years ago has remained there all the time, and is now once more in solution.

"The desert will, no doubt, continue to be a lake and the outlet of the river unless the breaks in the banks of the river are dammed by artificial means, which seems hardly possible, as the river has been flowing through the break in the stream 200 feet wide, four feet deep, and flowing at a velocity of five feet a second.

"It is an interesting fact to note that the military survey made in 1853 went over this ground and predicted the very thing which has now happened. The flooding of the desert will be a good thing for the surrounding country, for it does away with a large tract of absolutely useless land, so barren that it is impossible to raise there what the man in Texas said they mostly raised in his town, and it will increase the humidity of the surrounding territory. Nature has done with this piece of waste land what it has often been proposed to do by private enterprise or by public appropriation. Congress has often been asked to make an appropriation for that purpose."

Mr. McGillivray had also some interesting things to say about Death Valley, which he surveyed.

"It has been called a _terra incognita_ and a place where no human being could live. Well, it is bad enough, but perhaps not quite so bad as that. The great trouble is the scarcity of water and the intense heat. But many prospecting parties go there looking for veins of ore and to take out borax. The richest borax mines in the world are found there. The valley is about 75 miles long by 10 miles wide. The lowest point is near the center, where it is about 150 ft. below the level of the sea. Just 15 miles west of this central point is Telescope peak, 11,000 ft. above the sea, and 15 miles east is Mt. Le Count, in the Funeral mountains, 8,000 ft. high. The valley runs almost due north and south, which is one reason for the extreme heat. The only stream of water in or near the valley flows into its upper end and forms a marsh in the bed of the valley. This marsh gives out a horrible odor of sulphureted hydrogen, the gas which makes a rotten egg so offensive. Where the water of this stream comes from is not very definitely known, but in my opinion it comes from Owen's lake, beyond the Telescope mountains to the west, flowing down into the valley by some subterranean passage. The same impurities found in the stream are also found in the lake, where the water is so saturated with salt, boracic acid, etc., that one can no more sink in it than in the water of the Great Salt lake; and I found it so saturated that after swimming in it a little while the skin all over my body was gnawed and made very sore by the acids. Another reason why I think the water of the stream enters the valley by some fixed subterranean source is the fact that, no matter what the season, the flow from the springs that feed the marsh is always exactly the same.

"The heat there is intense. A man cannot go an hour without water without becoming insane. While we were surveying there, we had the same wooden cased thermometer that is used by the signal service. It was hung in the shade on the side of our shed, with the only stream in the country flowing directly under it, and it repeatedly registered 130°; and for 48 hours in 1883, when I was surveying there, the thermometer never once went below 104°."--_Boston Herald._

* * * * *

HEMLOCK AND PARSLEY.

By W.W. BAILEY.

The study of the order Umbelliferæ presents peculiar difficulties to the beginner, for the flowers are uniformly small and strikingly similar throughout the large and very natural group. The family distinctions or features are quite pronounced and unmistakable, and it is the determination of the genera which presents obstacles--serious, indeed, but not insurmountable. "By their fruits shall ye know them."

The Umbelliferæ, as we see them here, are herbaceous, with hollow, often striated stems, usually more or less divided leaves, and no stipules. Occasionally we meet a genus, like Eryngium or Hydrocotyle, with leaves merely toothed or lobed. The petioles are expanded into sheaths; hence the leaves wither on the stem. The flowers are usually arranged in simple or compound umbels, and the main and subordinate clusters may or may not be provided with involucres and involucels. To this mode of arrangement there are exceptions. In marsh-penny-wort (Hydrocotyle) the umbels are in the axils of the leaves, and scarcely noticeable; in Eryngium and Sanicula they are in heads. The calyx is coherent with the two-celled ovary, and the border is either obsolete or much reduced. There are five petals inserted on the ovary, and external to a fleshy disk. Each petal has its tip inflexed, giving it an obcordate appearance. The common colors of the corolla are white, yellow, or some shade of blue. Alternating with the petals, and inserted with them, are the five stamens.