happened to undertake his research on petroleum, or "rock oil" as it was more commonly called in those days.

When one speaks of Benjamin Silliman, Jr., it is impossible not to mention his father, for the two together—"Young Ben" and "Old Ben"—were largely responsible for introducing science to higher education in the United States. The two men worked closely—the career of one merging into the career of the other. "Old Ben" was a brilliant man, perhaps even more brilliant than his son whom we are honoring today, but on his graduation from Yale in 1796 the horizon had seemed rather narrow. "I don't want to be a doctor; I am not good enough for a priest; and lawyers are so plenty that they can hardly get a case apiece," he had said. Nevertheless, he turned to the study of law with some work on the family farm thrown in. But this did not last long.

When "Old Ben" was 23, President Timothy Dwight, of Yale, asked him to become professor of chemistry and natural history. It is hard to imagine what a startling, even radical, request this must have been, for at that time no one in this country had ever heard of a professor of chemistry. Those were the days when Latin and Greek buttressed with a little philosophy and mathematics were deemed sufficient education for any man. Besides, there was the fact that, as Silliman himself undoubtedly pointed out, he didn't know a thing about chemistry. But President Dwight, with faith in Silliman as a man, was ready for that. "Who at Yale knows more?" Dwight must have replied. "We'll pay your expenses while you learn all you can." So Silliman went to Philadelphia, the nation's only scientific center, thanks to the still-lingering influence of Ben Franklin. And when he had learned all he could in Philadelphia, the elder Silliman went to Europe for two years. There he met and talked with every important man of science in England, France and Germany.

Back at Yale, "Old Ben" began a career that was to last for more than half a century. He was the pioneer in the teaching of science

but his teaching was confined entirely to the classroom and lecture platform. The science of chemistry was too young to allow students to do any laboratory work themselves. As a matter of fact, there was no laboratory and very little apparatus. An old letter of Silliman's tells of the difficulty of obtaining even the simplest equipment:

> "I had picked up a few glass retorts in Philadelphia, and I made application to Mr. Mather, a manufacturer of glass in East Hartford, a few years later, to make some for me. On stating my wish, he said he had never seen a retort, but if I would send him one as a pattern, he did not doubt he could make them. I had a retort whose neck or tube was broken off near the ball, but as no portion was missing, and the two parts exactly fitted each other, I sent this retort and its neck in a box, never dreaming that there could be a blunder. In due time, however, my dozen of glass retorts of East Hartford manufacture arrived, carefully boxed and all sound, except that they were all cracked off at the neck exactly where the pattern was fractured, and broken neck and ball lay in state like decapitated kings in their coffins."

So long as chemistry was confined to the lecture platform, no real progress could be made. At this point we return to "Young Ben," for it was he who put college chemistry into the laboratory, thus opening the way for the advances which only laboratory research can bring.

In 1842 "Young Ben" was helping his father edit the *American Journal of Science*, founded in 1818 and known throughout the world at that time as "Silliman's Journal." But he was impatient to do more and soon his impatience led him to a course of action.

At the edge of the campus stood an old, ramshackle, whitewashed brick building. Formerly used as the President's house, it had stood vacant for several years and was now available for rent. "Young Ben" scraped together some cash, paid the rental, bought some

equipment and opened his own school for advanced students, namely, those who had completed his father's lecture courses and who, like himself, were impatient to move on and learn more through their own experiments. Silliman's private School of Analytical Chemistry was the first college research laboratory in this country and his students could well be called the first science graduate students. Student fees paid only a fraction of the expense of running the new laboratory. The rest came out of Silliman's own pocket.

Yale College, I must admit, ignored the new venture, except to make sure that the rent was paid on time. As a contemporary of Silliman's remarked: "The College, indeed, had no money to give, but even if it had, it is more than doubtful that it would have given it."

No one at that time, however enthusiastic, ever dreamed of the supreme importance which the natural sciences were soon to assume in every well-devised scheme of education. The impression, indeed, seemed generally to prevail that chemistry, like virtue, must be its own reward. But the laboratory prospered nevertheless. By 1846 the College gave it official recognition (but still no money) and named Silliman professor of general and applied chemistry. That year his reputation—already substantial because of his association with the *American Journal of Science*—received a tremendous boost with the publication of his *First Principles of Chemistry*, a textbook which ran through three editions in as many years and which sold more than 50,000 copies all told. That would be quite a success story even in 1955.

By 1854 Silliman and his work were known throughout the country. Glancing at the records of his research in those years it is hard to see how he had any time for sleep. He had scores of students working and experimenting under his personal direction in the laboratory. The United States was on the verge of its first great wave of industrial expansion and Silliman was always willing—as a fellow faculty member put it—to have “his aid invoked in various matters

connected with the practical arts where a knowledge of scientific principles is involved.” He had published reports on everything from iron ore to “an analysis of the blue mud of New Haven harbor”; from a treatise on the manufacture of water gas to a study of the chemicals found in a sample of water from the Dead Sea.

It should be noted that Silliman never made any original scientific discoveries, either experimental or theoretical. His interest in science was largely from a practical viewpoint. His advice was much sought after on all kinds of practical matters where science could be applied. If he were alive today, I like to think that he would be one of our leading chemical engineers. His reputation is based mainly on his

Old Eli in contrast. Inset photo shows the building Silliman used as his first laboratory. The other photo is of Sheffield Hall and Sterling Tower, a modern landmark on the Yale campus.

ability as a lecturer, a writer of two widely used texts and his many
papers and reports on the application of science to the practical arts
and to manufacture.

So the stage was set for his experiments on petroleum. Now I'd
like to turn away from Silliman in New Haven in 1854 for a moment
and go north to Hanover, New Hampshire, where the chain of events
that led up to Silliman's report began. In the fall of 1853 Dr. Francis
Beattie Brewer, a Dartmouth graduate and resident of Titusville,
Pennsylvania, carried a bottle of rock oil with him on a visit to
Dartmouth. He showed it to two Dartmouth professors, one of whom
was Oliver P. Hubbard, Silliman's brother-in-law and a Yale gradu-
ate who had studied under the elder Silliman for many years. Hub-
bard examined the oil and expressed the opinion that it was valuable,
but that it could hardly become an article of commerce unless it
could be obtained in large quantities.

A few weeks later another Dartmouth graduate, George H. Bissell, saw the little bottle of oil and inquired about it. Bissell had imagination, and his enthusiasm was aroused by what he heard of the possibilities of the oil. Returning to New York he interested his business partner, Jonathan G. Eveleth, and a man was sent to Titusville to examine the oil-bearing land. The man's excited report was all that Bissell and Eveleth wanted to hear. Immediately they set out to raise the capital necessary to buy land and attempt, in one way or another, to get oil. But this was no easy task. No one seemed interested in risking money on a thick, evil-smelling substance which, as yet, had no important commercial uses. Actually some petroleum was being sold on the market, not as a lubricant or illuminant but as a medicinal cure-all. Since 1849 Samuel M. Kier, of Pittsburgh, had been selling his "rock oil" in half-pint bottles for 50 cents. Kier was quite an ad man. His product would cure everything from gout to indigestion, from deafness to corns. As a pair of couplets in one of his advertisements claimed, rock oil was:

The Healthful balm, from Nature's secret spring,
The bloom of health, and life, to man will bring;
As from her depths the magic liquid flows,
To calm our sufferings and assuage our woes.

This may have been a profitable venture for Mr. Kier, but it was
hardly enough to convince New York capitalists to back Messrs.
Bissell and Eveleth. So, at the suggestion of a friend, they went to
New Haven. There they found several men, headed by James M.
Townsend, a local banker, who were quite ready and willing to join
in the enterprise on one condition. The condition was that Prof. Ben-
jamin Silliman, Jr., of Yale College, be asked to analyze and report
on the rock oil. If Silliman's report was favorable, Bissell and Eveleth
could count them in.

So it was that a barrel of crude oil arrived at Professor Silliman's
laboratory in the fall of 1854. He set to work immediately, probably
conducting his experiments in the room that was the scullery of the
former President's house. He worked through the long winter and on
April 16, 1855, submitted his report. It is headed:

REPORT
ON THE
ROCK OIL, OR PETROLEUM,

FROM
VENANGO CO., PENNSYLVANIA,
WITH SPECIAL REFERENCE TO ITS USE FOR ILLUMINATION AND
OTHER PURPOSES.

The report begins with a listing of several places around the world where petroleum seepages occur and mentions its production in "vast quantities" in India. But he finds that this oil from Venango County is unlike any other reported. He then states: "The question naturally arises, of what value is it in the arts and for what uses can it be employed? To enable you to answer these inquiries has been the object of my researches."

Silliman then begins to record the results of his separate experi-

ments. As a first step he made a fractional distillation and separated it into eight products at temperatures ranging from 100 to 220°C. A residue of about 47 percent remained in the retort, which he described as a "dark, thick resinous-looking varnish." He concluded that the oil was a complex mixture of compounds all consisting only of carbon and hydrogen. Each product was carefully examined, subjected to various tests and discussed in detail. "Clean copper remained untarnished in the oil which had thus been prepared, showing its fitness for lubrication, so far as absence of corrosive quality is concerned," the report states. He decomposed (we call it "cracked") some of the oil fractions at red heat and made a gas which, he said, gave "the most perfect flame" in an Argand burner. He did not pursue these experiments further because "other products, now known and in use, for gas making, might be employed at less expense for this purpose, than your oil." He made many tests by burning the oil fractions in lamps for illumination. He submitted the burning lamps to "the most experienced lampists," who pronounced the results to be good. He even devised a photometer for getting a quantitative measure of the illuminating power and he is obviously very pleased with the results he got from it.

At this point Silliman procured a copper retort with a thermometer and went on with the fractional distillation at several stages up to 750 degrees Fahrenheit. "It now became necessary," he writes, "to employ dry hickory wood as a fuel, to obtain flame and sufficient heat to drive over any further portions of the residue remaining in the alembic." He goes on to say: "The result of this graduated distillation, at a high temperature, is that we have obtained over 90 percent of the whole crude product in a series of oils, having valuable properties, although not all equally fitted for illumination and lubrication."

But even Professor Silliman's sober scientific restraint could not hide his enthusiasm as he ended his report with these sentences:

> "It appears to me that there is much ground for encouragement

in the belief that your Company have in their possession a raw material from which, by simple and not expensive process, they may manufacture very valuable products." (What a magnificent understatement this has turned out to be!) "It is worthy of note that my experiments prove that nearly the whole of the raw product may be manufactured without waste, and this solely by a well directed process which is in practice, one of the most simple of all chemical processes."

The report was finished but now the delays began. First, Eveleth and Bissell lacked the money to pay Silliman's bill of $526.08 and he was canny enough not to hand over the report until the money was forthcoming. When the money was borrowed and the report printed by J. H. Benham's steam power press in New Haven, many rushed to invest their money in this new venture which was bolstered by the prestige of Silliman's name. The records of the company that was formed are a model of corporate confusion, such confusion that no real effort was made to get oil until 1858, three years after Silliman's report. Then a new company was formed. Edwin L. Drake, an unemployed railroad conductor and an ingenious jack-of-all-trades, was hired at $1,000 a year to go to Titusville. The rest is a familiar story: Drake's persistence in the face of bad luck and disappointment, near-abandonment of the project, and triumphant success when the first well came in on that Saturday afternoon, August 27, 1859.

Ironically, this first venture never made a cent. The New Haven company, plagued by poor management, was sold out in 1864 after having expended and received about $50,000 from first to last. Professor Silliman, himself an investor, lost $400. Others managed to break even. Drake fell sick and died a pauper in 1880. But although the company failed, the petroleum industry prospered and grew without faltering. Within months the nation knew that it did indeed possess, in the prophetic and understated words of Benjamin Silliman, Jr., a raw material from which may be manufactured "very valuable products." Thank you.

REPORT.

Messrs. Eveleth, Bissell & Reed,

GENTLEMEN,—

I HEREWITH offer you the results of my somewhat extended researches upon the Rock Oil, or Petroleum, from Venango County, Pennsylvania, which you have requested me to examine with reference to its value for economical purposes.

Numerous localities, well known in different parts of the world, furnish an oily fluid exuding from the surface of the earth, sometimes alone in "tar springs," as they are called in the western U. S.; frequently it is found floating upon the surface of water in a thin film, with rainbow colors, or in dark globules, that may, by mechanical means, be separated from the fluid on which it swims.

In some places wells are sunk for the purpose of accumulating the product in a situation convenient for collection by pumping the water out. The oil exudes on the shores of Lakes and Lagoons, or rises from springs beneath the bed of Rivers. Such are the springs of Baku, in Persia, and the wells of Amiano, in the duchy of Parma, in Italy. The usual geological position of the rocks furnishing this natural product, is in the coal measures—but it is by no means confined

Reprinted in 1955 by ETHYL CORPORATION, New York

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to this group of rocks, since it has been found in deposits much more recent, and also in those that are older—but in whatever deposits it may occur, it is uniformly regarded as a product of vegetable decomposition. Whether this decomposition has been effected by fermentation only, or by the aid of an elevated temperature, and distilled by heated vapor, is perhaps hardly settled.

It is interesting, however, in this connection to remember, that the distillation, at an elevated temperature, of certain black bituminous shales in England and France, has furnished large quantities of an oil having many points of resemblance with Naphtha, the name given to this colorless oil, which is the usual product of distilling Petroleum. The very high boiling point of most of the products of the distillation of the Rock Oil from Venango County, Pa., would seem to indicate that it was a pyrogenic (fire produced) product.

Bitumen, Asphaltum, Mineral Pitch, Chapapote, &c., &c., are names variously given to the more or less hard, black resinous substance which is produced usually from the exposure of Petroleum to the air, and is found either with or without the fluid Naphtha or Petroleum. The most remarkable examples of the occurrence of these substances so intimately connected with the history of Rock Oil, are the Lake Asphaltdites or the Dead Sea, so memorable in history, the well known Bitumen Lake of Trinidad, and the deposits of mineral pitch or Chapapote in Cuba. In one of the provinces of India, vast quantities of Petroleum are annually produced, the chief consumption being local, for fuel and lights, but a portion is also exported to Europe for the production of Naphtha. In the United States, many points on the Ohio

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and its tributaries, are noted as producing this oil; nearly all of them within the coal measures. A detailed history of these various localities can be found recorded in books of science, and their repetition here would be out of place.

### General Characters of the Crude Product.

The Crude oil, as is gathered on your lands, has a dark brown color, which, by reflected light, is greenish or bluish. It is thick even in warm weather—about as thick as thin molasses. In very cold weather it is somewhat more stiff, but can always be poured from a bottle even at 15° below zero. Its odor is strong and peculiar, and recalls to those who are familiar with it, the smell of Bitumen and Naphtha. Exposed for a long time to the air, it does not thicken or form a skin on its surface, and, in no sense, can it be called a drying oil. The density of the Crude oil is 882, water being 1000. It boils only at a very high temperature, and yet it begins to give off a vapor at a temperature not greatly above that of boiling water. It takes fire with some difficulty, and burns with an abundant smoky flame. It stains paper with the appearance of ordinary fat oils, and feels smooth and greasy between the fingers. It is frequently used in its crude state to lubricate coarse machinery. In chemical characters, it is entirely unlike the fat oils. Most of these characters are common to Petroleum from various places. In one important respect, however, the product of your lands differ from that obtained in other situations, that is, it does not, by continued exposure to the air, become hard and resinous like mineral pitch or bitumen. I have been informed by those who have visited the locality, that on the surface of the earth about the springs which furnish your oil,

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there is no crust or deposit of this sort such as I have seen in other situations where Petroleum or mineral tar is flowing. This difference will be seen to be of considerable importance, as it is understood and represented that this product exists in great abundance upon your property, that it can be gathered wherever a well is sunk in the soil, over a great number of acres, and that it is unfailing in its yield from year to year. The question naturally arises, of what value is it in the arts, and for what uses can it be employed? To enable you to answer these inquiries has been the object of my researches.

Examination of the Oil.

To determine what products might be obtained in the oil, a portion of it was submitted to fractional distillation.* The temperature of the fluid was constantly regulated by a thermometer, the heat being applied first by a water bath, and then by a bath of linseed oil. This experiment was founded upon the belief that the crude product contained several distinct oils, having different boiling points. The quantity of material used in this experiment, was 304 grammes. The thermometer indicated the degrees of the Centigrade scale, but, for convenience, the corresponding degrees of Fahrenheit's scale are added. The water bath failed to distil any portion of the oil at 100°C. (=212°Fah.) only a small quantity of acid water came over. An oil bath, (linseed oil,) was then substituted, and the temperature was regularly raised by slow degrees until distillation commenced. From that point the heat was successively raised by stages of ten de-

* Fractional distillation is a process intended to separate various products in mixture, and having unlike boiling points, by keeping the mixture contained in an alembic at regulated successive stages of temperature as long as there is any distil-late at a given point, and then raising the heat to another degree, &c.

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grees, allowing full time at each stage for complete distillation of all that would rise at that temperature before advancing to the next stage. The results of this tedious process are given in the annexed table—304 Grammes of Crude oil, submitted to fractional distillation, gave :

<table><thead><tr><th></th><th>Temperature.</th><th>Quantity.</th></tr></thead><tbody><tr><td>1st Product at 100°C.=212°Fah. (acid water,)</td><td>5 Gms.</td><td></td></tr><tr><td>2d</td><td>" " 140°C. to 150°C.=284° to 302°Fah.</td><td>26 "</td></tr><tr><td>3d</td><td>" " 150°C. to 160°C.=302° to 320°Fah.</td><td>29 "</td></tr><tr><td>4th</td><td>" " 160°C. to 170°C.=320° to 338°Fah.</td><td>38 "</td></tr><tr><td>5th</td><td>" " 170°C. to 180°C.=338° to 356°Fah.</td><td>17 "</td></tr><tr><td>6th</td><td>" " 180°C. to 200°C.=356° to 392°Fah.</td><td>16 "</td></tr><tr><td>7th</td><td>" " 200°C. to 220°C.=392° to 428°Fah.</td><td>17 "</td></tr><tr><td>8th</td><td>" " 220°C. to 270°C.=428° to 518°Fah.</td><td>12 "</td></tr><tr><td>Whole quantity distilled by this method,</td><td>160</td></tr><tr><td>Leaving residue in the retort,</td><td>144</td></tr><tr><td>Original quantity,</td><td>304</td></tr></tbody></table>

Product No. 1, as above remarked, was almost entirely water, with a few drops of colorless oil, having an odor similar to the original fluid, but less intense.

Product No. 2 was an oil perfectly colorless, very thin and limpid, and having an exceedingly persistent odor, similar to the crude oil, but less intense.

Product No. 3 was tinged slightly yellow, perfectly transparent, and apparently as limpid as the 2d product, with the same odor.

Product No. 4 was more decidedly yellowish than the last, but was in no other respect distinguishable from it.

Product No. 5 was more highly colored, thicker in consistency, and had a decided empyreumatic odor.

Product No. 6. This and the two subsequent products were each more highly colored and denser than the preced-

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ing. The last product had the color and consistency of honey, and the odor was less penetrating than that of the preceding oils. The mass of crude product remaining in the retort, (equal 47.4 per cent.,) was a dark, thick, resinous looking varnish, which was so stiff, when cold, that it could be inverted without spilling. This showed no disposition to harden or skin over by exposure to the air. The distillation was arrested at this point in glass, by our having reached the limit of temperature for a bath of linseed oil. The density of the several products of this distillation, shows a progressive increase, thus:

<table><tr><td>No. 2,</td><td>density, .733</td></tr><tr><td>No. 3,</td><td>" .752</td></tr><tr><td>No. 4,</td><td>" .766</td></tr><tr><td>No. 5,</td><td>" .776</td></tr><tr><td>No. 6,</td><td>" .800</td></tr><tr><td>No. 7,</td><td>" .848</td></tr><tr><td>No. 8,</td><td>" .854</td></tr></table>

To form an idea of the comparative density of these several products, it may be well to state, that Sulphuric Ether, which is one of the lightest fluids known, has a density of .736, and Alcohol, when absolutely pure, .815.

The boiling points of these several fluids present some anomalies, but are usually progressive, thus, No. 2 gave signs of boiling at 115° C. (=239 Fah.) and boiled vigorously, and remained constant at 225° C. to 228° C., (=437° to 442° Fah.) No. 3 began to boil 120°, (=248° Fah.,) rose to 270° (=518° Fah.,) where it remained constant. No. 4 began to vaporise at 140°, (=284° Fah.,) rose to 290°, (=554° Fah.,) where it remained constant. On a second heating the temperature continued to rise, and passed 305°, (=581 Fah.)

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No. 5 gave appearance of boiling at 160°, (=320° Fah., boiling more vigorously as the heat was raised, and was still rising at 308°, (=581° Fah.) No. 6 commenced boiling at 135°, (=275° Fah.,) boiled violently at 160°, (=320° Fah.,) and continued rising above the range of the mercurial thermometer. No. 7 commenced ebullition at the same temperature as No. 6, and rose to 305°, (=581° Fah.,) where the ebullition was not very active. Much time was consumed in obtaining these results. We infer from them that the Rock Oil is a mixture of numerous compounds, all having essentially the same chemical constitution, but differing in density and boiling points, and capable of separation from each other, by a well-regulated heat.

The uncertainty of the boiling points indicates that the products obtained at the temperatures named above, were still mixtures of others, and the question forces itself upon us, whether these several oils are to be regarded as educts, (i. e., bodies previously existing, and simply separated in the process of distillation,) or whether they are not rather produced by the heat and chemical change in the process of distillation. The continued application of an elevated temperature alone is sufficient to effect changes in the constitution of many organic products, evolving new bodies not before existing in the original substance.

## Properties of the distilled Oils.

Exposed to the severest cold of the past winter, all the oils obtained in this distillation remained fluid. Only the last two or three appeared at all stiffened by a cold of 15° below zero, while the first three or four products of distillation retained a perfect degree of fluidity. Exposed to air,

2

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as I have said, they suffer no change. The chemical exam-
ination of these oils showed that they were all composed of
Carbon and Hydrogen, and probably have these elements
in the same numerical relation. When first distilled, they
all had an acid reaction, due to the presence of a small quan-
tity of free sulphuric acid, derived from the Crude oil. This
was entirely removed by a weak alkaline water, and even
by boiling on pure water. Clean copper remained untar-
nished in the oil which had been thus prepared, showing its
fitness for lubrication, so far as absence of corrosive quality
is concerned. The oils contain no oxygen, as is clearly
shown by the fact that clean potassium remains bright in
them. Strong *Sulphuric Acid* decomposes and destroys the
oil entirely. *Nitric Acid* changes it to a yellow, oily fluid,
similar to the changes produced by Nitric Acid on other oils.
*Hydrochloric*, *Chromic*, and *Acetic Acids*, do not affect it.
*Litharge* and other metallic oxyds do not change it, or con-
vert it in any degree to a drying oil. *Potassium* remains
in it unaffected, even at a high temperature. *Hydrates of
Potash, Soda*, and *Lime*, are also without action upon it.
*Chlorid of Calcium* and many other salts manifest an equal
indifference to it. Distilled with *Bleaching Powders* (chl-
rid of lime) and water, in the manner of producing chloro-
form, the oil is changed into a product having an odor and
taste resembling chloroform. Exposed for many days in an
open vessel, at a regulated heat below 212°, the oil gradually
rises in vapor, as may be seen by its staining the paper used
to cover the vessel from dust, and also by its sensible diminu-
tion. Six or eight fluid ounces, exposed in this manner in
a metallic vessel for six weeks or more, the heat never
exceeding 200°, gradually and slowly diminished, grew yel-

low, and finally left a small residue of dark brown lustrous
looking resin, or pitchy substance, which in the cold was
hard and brittle. The samples of oil employed were very
nearly colorless. This is remarkable when we remember
that the temperature of the distillation was above 500° Fah.
The oil is nearly insoluble in pure alcohol, not more than
4 or 5 per centum being dissolved by this agent. In Ether
the oil dissolves completely, and on gentle heating is left
unchanged by the evaporation of the Ether. India Rubber
is dissolved by the distilled oil to a pasty mass, forming a
thick black fluid which, after a short time, deposits the
india rubber. It dissolved a little Amber, but only sufficient
to color the oil red. It also dissolves a small portion of
Copal in its natural state; but after roasting, the Copal dis-
solves in it as it does in other oils.

Use for Gas making.

The Crude Oil was tried as a means of illumination. For
this purpose a weighed quantity was decomposed, by passing
it through a wrought iron retort filled with carbon, and
ignited to full redness. The products of this decomposition
were received in a suitable apparatus. It produced nearly
pure carburetted Hydrogen Gas, the most highly illuminating
of all the carbon gases. In fact, the oil may be regarded
as chemically identical with illuminating gas in a liquid
form. The gas produced equalled ten cubic feet to the
pound of oil. It burned with an intense flame, smoking in
the ordinary gas jet, but furnishing the most perfect flame
with the argand burner.

These experiments were not prosecuted further, because
it was assumed that other products, now known and in use,

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for gas making, might be employed at less expense for this
purpose, than your oil. Nevertheless, this branch of inquiry
may be worthy of further attention.

Distillation at a higher temperature.

The results of the distillation at a regulated temperature
in glass, led us to believe, that in a metallic vessel capable
of enduring a high degree of heat, we might obtain a much
larger proportion of valuable products. A copper-still, hold-
ing five or six gallons was therefore provided, and furnished
with an opening, through which a thermometer could be
introduced into the interior of the vessel. Fourteen imperial
quarts (or, by weight, 560 ounces) of the crude product
were placed in this vessel, and the heat raised rapidly to
about 280° C., (≈536° Fah.,) somewhat higher than the
last temperature reached in the first distillation. At this
high temperature the distillation was somewhat rapid, and
the product was easily condensed without a worm. The
product of the first stage was 130 ounces, (or over 28 per
cent.,) of a very light colored thin oil, having a density of
.792. This product was also acid, and as before, the acid was
easily removed by boiling with fresh water. The temperature
was now raised to somewhat above 300° C., (≈572° Fah.,)
and 123 ounces more distilled, of a more viscid and yellow-
ish oil, having a density of .865. This accounts for over
43 per cent. of the whole quantity taken. The temperature
being raised now above the boiling point of mercury, was
continued at that until 170 ounces, or over 31 per cent., of
a dark brown oil had been distilled, having a strong empy-
reumatic odor. Upon standing still for some time, a dark
blackish sediment was seen to settle from this portion, and

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on boiling it with water, the unpleasant odor was in a great
degree removed, and the fluid became more light colored
and perfectly bright. (It was on a sample of this that the
photometric experiments were made.) The next portion,
distilled at about 700° Fah., gave but about 17 ounces, and
this product was both lighter in color and more fluid than
the last. It now became necessary to employ dry hickory
wood as a fuel, to obtain flame and sufficient heat to drive
over any further portions of the residue remaining in the
alembic.

It will be seen that we have already accounted for over
75 per cent. of the whole quantity taken. There was a
loss on the whole process of about 10 per cent., made up, in
part, of a coaly residue that remained in the alembic, and
partly of the unavoidable loss resulting from the necessity
of removing the oil twice from the alembic, during the pro-
cess of distillation, in order to change the arrangements of
the thermometer, and provide means of measuring a heat
higher than that originally contemplated.

About 15 per cent. of a very thick, dark oil, completed
this experiment. This last product, which came off slowly
at about 750° Fah., is thicker and darker than the original
oil, and when cold is filled with a dense mass of pearly
crystals. These are Paraffine, a peculiar product of the
destructive distillation of many bodies in the organic king-
dom. This substance may be separated and obtained as a
white body, resembling fine spermaceti, and from it beauti-
ful candles have been made. The oil in which the crystals
float is of a very dark color, and by reflected light is blackish
green, like the original crude product. Although it distills
at so high a temperature, it boils at a point not very different

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from the denser products of the first distillation. The Paraffine, with which this portion of the oil abounds, does not exist ready-formed in the original crude product, but it is a result of the high temperature employed in the process of distillation, by which the elements are newly arranged.

I am not prepared to say, without further investigation, that it would be desirable for the Company to manufacture this product in a pure state, fit for producing candles, (a somewhat elaborate chemical process,) but I may add that, should it be desirable to do so, the quantity of this substance produced may probably be very largely increased, by means which it is now unnecessary to mention.

Paraffine derives its name from the unalterable nature of the substance, under the most powerful chemical agents. It is white, in brilliant scales of a greasy lustre; it melts at about 116°, and boils at over 700° Fah.; it dissolves in boiling alcohol and ether, and burns in the air with a brilliant flame. Associated with Paraffine are portions of a very volatile oil, *Eupione*, which boils at a lower temperature, and by its presence renders the boiling point of the mixture difficult to determine. I consider this point worthy of further examination than I have been able at present to give it, i. e., whether the last third, and possibly the last half, of the Petroleum may not be advantageously so treated as to produce from it the largest amount of Paraffine which it is able to produce.

The result of this graduated distillation, at a high temperature, is that we have obtained over 90 per cent. of the whole crude product in a series of oils, having valuable properties, although not all equally fitted for illumination and lubrication.

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A second distillation of a portion of the product which came over in the latter stages of the process, (a portion distilled at about 650° Fah., and having a high color,) gave us a thin oil of density about .750, of light yellow color and faint odor.

It is safe to add that, by the original distillation, about 50 per cent. of the Crude oil is obtained in a state fit for use as an illuminator without further preparation than simple clarification by boiling a short time with fair water.

*Distillation by High Steam.*

Bearing in mind that by aid of high steam, at an elevated temperature, many distillations in the arts are effected which cannot be so well accomplished by dry heat, I thought to apply this method in case of the present research. Instances of this mode of distillation are in the new process for Stearine candles, and in the preparation of Rosin Oil. I, accordingly, arranged my retort in such a manner that I could admit a jet of high steam into the boiler, and almost at the bottom of the contained Petroleum. I was, however, unable to command a jet of steam above 275° to 290° Fah., and, although this produced abundant distillation, it did not effect a separation of the several products, and the fluid distilled had much the same appearance as the Petroleum itself, thick and turbid. As this trial was made late in the investigation, I have been unable to give it a satisfactory issue, chiefly for want of steam of a proper temperature. But I suggest, for the consideration of the Company, the propriety of availing themselves of the experience already existing on this subject, and particularly among those who are concerned in the distillation of Rosin Oil—a product having many analogies with Petroleum in respect to its manufacture.

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Use of the Naphtha for Illumination.

Many fruitless experiments have been made in the course
of this investigation which it is needless to recount. I will,
therefore, only state those results which are of value.

1.—I have found that the only lamp in which this oil can be successfully burned is the Camphene lamp, or one having a button to form the flame, and an external cone to direct the current of air, as is now usual in all lamps designed to burn either Camphene, Rosin Oil, Sýlvic Oil, or any other similar product.

2.—As the distilled products of Petroleum are nearly or
quite insoluble in alcohol, burning fluid (i. e., a solution of
the oil in alcohol) cannot be manufactured from it.

3.—As a consequence, the oil cannot be burned in a hand
lamp, since, with an unprotected wick, it smokes badly.
Neither can it be burned in a Carcel's mechanical lamp, be-
cause a portion of the oil being more volatile than the rest,
rises in vapor on the elevated wick required in that lamp,
and so causes it to smoke.

I have found all the products of distillation from the cop-
per still capable of burning well in the Camphene lamp, ex-
cept the last third or fourth part, (i. e., that portion which
came off at 700° F. and rising, and which was thick with the
crystals of Paraffine.) Freed from acidity by boiling on water
the oils of this distillation burned for 12 hours without in-
juriously coating the wick, and without smoke. The wick
may be elevated considerably above the level required for
Camphene without any danger of smoking, and the oil shows
no signs of crusting the wick tubes with a coating of Resin,
such as happens in the case with Camphene, and occasions
so much inconvenience. The light from the rectified Naph-

( 17 )

tha is pure and white without odor. The rate of consump-
tion is less than half that of Camphene, or Rosin Oil. The
Imperial pint, of 20 fluid ounces, was the one employed—a
gallon contains 160 such ounces. A Camphene lamp, with
a wick one inch thick, consumed of rectified Naphtha in one
hour, 1 3-4 ounces of fluid. A Carcel's mechanical lamp of
7-8 inch wick, consumed of best Sperm Oil, per hour, 2
ounces. A "Diamond Light" lamp, with "Sylvic Oil," and
a wick 1 1-2 inch diameter, consumed, per hour, 4 ounces.

I have submitted the lamp burning Petroleum to the in-
spection of the most experienced lampists who were acces-
sible to me, and their testimony was, that the lamp burn-
ing this fluid gave as much light as any which they had
seen, that the oil spent more economically, and the uniformity
of the light was greater than in Camphene, burning for 12
hours without a sensible dimunition, and without smoke. I
was, however, anxious to test the amount of light given
more accurately than could be done by a comparison of opin-
ions. With your approbation I proceeded therefore to have
constructed a photometer, or apparatus for the measurement
of light, upon an improved plan. Messrs. Gunow, scientific
artists of this city, undertook to construct this apparatus, and
have done so to my entire satisfaction. This apparatus I
shall describe elsewhere—its results only are interesting here.
By its means I have brought the Petroleum light into rigid
comparison, with the most important means of artificial illu-
mination. Let us briefly recapitulate the results of these.

Photometric Experiments.

The *unit* adopted for comparison of intensities of illumina-
nation is Judd's Patent Sixes Sperm Candle.

3

(18)

The Sperm Oil used was from Edward Mott Robinson, of New Bedford—the best winter Sperm remaining fluid at 32° Fah. The Colza Oil and Carcel's lamps were furnished by Dardonville, lampist, Broadway, New York.

The Gas used was that of the New Haven Gas Light Co., made from best Newcastle coal, and of fair average quality.

The distance between the standard candle, and the illuminator sought to be determined was constantly 150 inches—the Photometer traversed the graduated bar in such a manner as to read, at any point where equality of illumination was produced, the ratio between the two lights. I quote only single examples of the average results, and with as little details as possible, but I should state that the operations of the Photometer was so satisfactory that we obtained constantly the same figures when operating in the same way, evening after evening, and the sensitiveness of the instrument was such that a difference of one half inch in its position was immediately detected in the comparative illumination of the two equal discs of light in the dark chamber. This is, I believe, a degree of accuracy not before obtained by a Photometer.

Table of illuminating power of various artificial lights compared with Judd's patent candles as a unit.

<table><thead><tr><th>Source of Light.</th><th>Ratio to Candle—1.</th></tr></thead><tbody><tr><td>Gas burning in Scotch fish-tail tips, 4 feet to the hour,</td><td>1 : 5.4</td></tr><tr><td>“ “ “ “ 6 “ “</td><td>1 : 7.55</td></tr><tr><td>“ “ Cornelius “ “ 6 “ “</td><td>1 : 6.2</td></tr><tr><td>“ “ English Argand burner 10 “ “</td><td>1 : 16</td></tr><tr><td>Rock Oil, burning in 1 inch wick Camphene Lamp, consuming 1 3-4 ounces of fluid the hour,</td><td>1 : 8.1</td></tr><tr><td>Carcel's Mechanical Lamp, burning best Sperm Oil, 2 ounces fluid to the hour, wick 7-8 of an inch,</td><td>1 : 7.5</td></tr><tr><td>Carcel's “ “ “ “ Colza Oil,</td><td>1 : 7.5</td></tr><tr><td>Camphene Lamp, (same size as Rock Oil above,) burning best Camphene, 4 ounces fluid per hour,</td><td>1 : 1.1</td></tr><tr><td>“Diamond Light” by “Sylvic Oil,” in 1 1-2 inch wick, 4 ounces per hour,</td><td>1 : 8.1</td></tr></tbody></table>

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From this table it will be seen that the Rock Oil Lamp was somewhat superior in illuminating power to Carcel's Lamp of the same size, burning the most costly of all oils. It was also equal to the “Diamond Light” from a lamp of one half greater power, and consequently is superior to it in the same ratio in lamps of equal power. The Camphene lamp appears to be about one fifth superior to it, but, on the other hand, the Rock Oil surpasses the Camphene by more than one half in economy of consumption, (i. e., it does not consume one half so much fluid by measure,) and it burns more constantly. Compared with the Sylvic Oil and the Sperm, the Rock Oil gave on the ground glass diaphgram the whitest disc of illumination, while in turn the Camphene was whiter than the Rock Oil light. By the use of screens of different colored glass, all inequalities of color were compensated in the use of the photometer, so that the intensity of light could be more accurately compared. Compared with Gas, the Rock Oil gave more light than any burner used except the costly Argand consuming ten feet of gas per hour. To compare the cost of these several fluids with each other we must know the price of the several articles, and this varies very much in different places. Thus, gas in New Haven costs $4 per 1,000 feet, and in New York $3.50 per 1,000 in Philadelphia $2.00 per 1,000, and in Boston about the same amount.

Such Sperm Oil as was used costs $2.50 per gallon, the Colza about $2, the Sylvic Oil 50 cents, and the Camphene 68 cents—no price has been fixed upon for the rectified Rock Oil.

I cannot refrain from expressing my satisfaction at the results of these photometric experiments, since they have given

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the Oil of your Company a much higher value as an illuminator than I had dared to hope.

*Use of the Rock Oil as a Lubricator for Machinery.*

A portion of the rectified oil was sent to Boston to be tested upon a trial apparatus there, but I regret to say that the results have not been communicated to me yet. As this oil does not gum or become acid or rancid by exposure, it possesses in that, as well as in its wonderful resistance to extreme cold, important qualities for a lubricator.

*Conclusion.*

In conclusion, gentlemen, it appears to me that there is much ground for encouragement in the belief that your Company have in their possession a raw material from which, by simple and not expensive process, they may manufacture very valuable products.

It is worthy of note that my experiments prove that nearly the *whole* of the raw product may be manufactured without waste, and this solely by a well directed process which is in practice, one of the most simple of all chemical processes.

There are suggestions of a practical nature, as to the economy of your manufacture, when you are ready to begin operations, which I shall be happy to make, should the Company require it—meanwhile, I remain, gentlemen,

Your ob't serv't,

B. SILLIMAN, JR.,

*Prof. of Chemistry in Yale College.*

NEW HAVEN, April 16, 1855.

ERRATUM.—On page 8, tenth line from bottom, for 815, read 800.