The manufacture of commercial products from petroleum dates from the discovery of the crude material in large quantities in Pennsylvania. From the time the wells of that region first attracted attention, numerous individuals, some of whom were engaged in the manufacture of kerosene (see Kerosene), began to experiment with petroleum with a view to obtain materials resembling the products that were then being distilled from coal. These earlier experiments and the small cost of producing kerosene from this source very soon led to the substitution of petroleum for coal as the crude material for illuminating oil, and almost all the manufacturers changed their apparatus and establishments into petroleum refineries. The high price of kerosene at that time left such a very wide margin for profit that the methods of carrying on the business, crude as they were in almost every particular, were still very successful. In 1861, three years after petroleum first attracted special notice, there were refineries in nearly every city on the Atlantic coast, from Baltimore to Portland, and the oil regions were full of them; but it was four years later before coal was entirely disused in one or two establishments. For several years the only petroleum product considered of value was kerosene.

The light and heavy products were either used as fuel or thrown away. As the profits of the business were lessened from extensive competition, attempts were made to utilize the "by-products." One after another found useful applications, until now at least ten commercial articles are obtained, and some of them are consumed in enormous quantities. These are:

ARTICLES.

Sp.gr.

Baume.

Boiling point.

Rhigoalene ..................................................

•625

• • •

65° F.

Gasolene...

•665

85°

120

C Naphtha....

•706

70

180

B"......................

•724

67

220

A"......................

•742

65

300

Kerosene....

•804

45

350

Mineral sperm oil....

•847

36

425

Neutral lubricating oil....

•883

29

575

Paraffine " "...........

• • •

..

Paraffine wax....

•848

• • •

• •.

Residuum....

..

..

...

Rhigolene is the most volatile fluid that can be produced by condensing the first portions distilled from gasolene in a mixture of ice and salt. It is the lightest of all known fluids, and its evaporation at ordinary temperatures is so rapid as to cause the mercury to descend to - 19° F. in 20 seconds. It was prepared at the suggestion of Dr. H. J. Bigelow of Boston, and has been used to a considerable extent for producing local anaesthesia in surgical operations. Gasolene is the lightest product from petroleum that is produced in large quantities. It is used in the carburetters of automatic gas machines, and is admirably adapted to such purposes. A, B, and O naphthas are applied to a variety of uses in mixing paiuts and varnishes, and dissolving resins and other substances; but they have little commercial value, as their uses are quite limited. Kerosene has already been discussed. (See Kerosene.) Mineral sperm is the name given by Joshua Merrill, of the Downer kerosene oil company, to a petroleum product discovered by him. This is an illuminating oil intermediate in density between kerosene and lubricating oil. It is volatile only at very high temperatures, and is consequently free from the objections that have been urged against more easily inflammable oils.

As this oil has very little odor and will not take fire at any temperature below 300° F., it is especially valuable for use on railroads and ocean steamers. Neutral lubricating oil is another product discovered' by Mr. Merrill. He has prepared it of a light straw color, and with but little more taste or odor than sweet oil of almonds. It is by far the most pleasing and valuable lubricating oil yet prepared from any mineral source. The so-called paraffine lubricating oils, though of about the same density, contain a certain proportion of lighter and more volatile oils, which have a very pungent odor and burning acrid taste. These are unavoidably formed during the distillation of the heavier portions of the crude petroleum. By distilling in such a manner that the oils are never heated above their boiling points, this lighter oil is removed, and the neutral odorless oil is left in the still. Mixtures containing as much as 80 per cent, of this oil to 20 per cent, of sperm or other animal oil have the odor and taste of the animal oil. Both these mixtures and the pure oils have been used instead of the animal oils in immense quantities for oiling wool and machinery, the latter being considered especially valuable for oiling spindles in cotton mills.

The ordinary paraffine lubricating oils are of various qualities, much depending upon the care and expense involved in their preparation. Those prepared by simply frationing the distillate from petroleum are dark-colored, of very rank disagreeable odor, and are adapted to comparatively few uses, while some of the better qualities are nearly as valuable as the neutral oil prepared by Mr. Merrill. Paraffine wax has been described elsewhere. (See Paraffine.) Residuum is the black residue remaining in the still from the distillation of crude petroleum. It is used by the manufacturers of paraffine and lubricating oils, and also to a limited extent for lubricating heavy journals. - The crude oil is stored in large, often enormous wrought-iron tanks. When it is shipped in wooden barrels they are coated with glue upon the inside. For transportation on long voyages the lighter products, including kerosene, are put up in tin cans holding five gallons each, and hermetically sealed by soldering on the cover. The crude oil, as it flows from the wells or pumps, is received into large tanks, where it is allowed to stand for some time in order that the water may separate and settle to the bottom.

When the wells are some distance from a railroad track, the oil is often transported to the track by being forced through a pipe laid along the ground. Large quantities have been floated down the Alleghany river in scows and barges called " flats." Many of the large establishments transport the crude oil in what are called tank cars. These are ordinary platform cars, upon each of which are constructed two large tanks. These are filled at the wells and carried in long trains to all parts of the country. When they reach their destination they are emptied into iron tanks, often of immense size, when the oil is again allowed to settle so that the last traces of water and any sand or other impurity may be removed. - The apparatus for manufacturing petroleum consists of stills of various forms and sizes, with worms for condensing the vapors, and agitators in which the oils are treated with chemicals. The stills are usually cylindrical, and are placed either on one end or horizontally. They are either cast iron with wrought-iron bottoms or made wholly of boiler iron, and hold from 1,000 to 80,000 gallons. The smaller sizes are heated by one fire, the larger by several. Sometimes the stills are encased in wood or brick work to prevent loss of heat.

Superheated steam is frequently introduced into the stills, especially during the distillation of the heavy oils. The very large stills recently constructed are used for carrying on the process known as " cracking." After the removal of the gasolene and different grades of naphtha, the remainder is subjected to destructive distillation. Any method that will heat the vapors above the boiling point of the oil will decompose the heavy oil, with deposition of carbon and the production of lighter oils richer in hydrogen. This effect has been produced by distilling under pressure; but the method usually employed is the one before mentioned. The distillation is kept up in such a manner that as the temperature increases and the heavy oils pass into vapor, the vapors are condensed upon the high dome of the still and either fall back in drops or flow down the sides. In either case they reach the surface of the boiling oil beneath, which has meantime been heated above the boiling point of that which falls upon it. The result is a decomposition of the latter into a more volatile oil containing proportionally more hydrogen, and carbon which is deposited.

This process may be continued until nothing remains in the still but coke; but it is not usually carried to that point, as the coke is difficult to remove from the still. The tarry matter left in the still is known in commerce as " residuum." The treatment of the oils is confined to the heavier kinds, including kerosene. The naphthas do not require treatment. In many establishments all the oils treated are alternately agitated with about 5 per cent, of strong sulphuric acid and the same amount of strong solution of caustic soda. In others, solution of caustic soda is put into the stills, and sometimes the soda is used solid. The sulphuric acid removes a number of unstable compounds, by decomposing some of them and uniting with others. The caustic soda removes the excess of acid and acid compounds, and leaves the oils pure. The odor of the crude distilled oils is exceedingly offensive; the action of the caustic soda removes these disgusting compounds, and gives the finished oils the peculiar balsamic odor by which they are distinguished. The spent sulphuric acid is technically known as "sludge," and is used by the manufacturers of superphosphate of lime. The spent caustic soda is often recovered as a carbonate and reconverted into caustic soda.

Nitric acid and bichromate of potash have also been used in place of sulphuric acid. In many of the older refineries the oil was exposed in shallow tanks beneath a skylight, in a manner exactly similar to the treatment employed for bleaching sperm oil. This is an admirable method for obtaining a complete separation of the last minute particles of caustic soda, but it is not equal to finishing by a last distillation, which is the method now employed in the best establishments. - The demand for gasolene for automatic gas machines has led to the establishment of a few manufactories in which this very volatile product is separated from the heavier grades of naphtha. Other separate establishments have been erected for the manufacture of paraffine and lubricating oils from residuum. These purchase the heavy waste products from the large kerosene manufactories, and by special processes convert it into useful commercial articles. - The manufacture of petroleum products from the crude oil is carried on either to obtain the largest number of products of the finest quality, or to obtain the largest yield of kerosene without regard to any other product.

Probably the finest petroleum refinery in America,, if not in the world, is that of the Downer kerosene oil company of Boston, Mass., and Corry, Pa., of which Joshua Merrill is the manufacturing chemist. Mr. Merrill began the manufacture of hydrocarbon oils for illuminating and other purposes as early as 1852, and from that date until the introduction of petroleum in 1860 a great variety of crude materials had been subjected to his skilful treatment with unvarying success. The works in Boston were originally built for the working of coal, boghead shale, and albertite, but since 1865 nothing but petroleum has been used there. All of the products enumerated above are manufactured there excepting paraffine lubricating oil and residuum. The branch establishment at Corry, Pa., is used only for the distillation of crude petroleum, the distillates being shipped to Boston for treatment. The processes employed at Boston are as follows: The crude oil is pumped from the tank cars into settling tanks placed under ground. After settling, it is pumped into large wrought-iron stills or upright cylinders which hold about 12,000 gallons each. In these stills the oil is heated by steam alone, which removes the various grades of naphtha, they constituting about 15 per cent, of the crude petroleum.

These distillates are condensed in iron pipes surrounded by cold water, and conducted into different receptacles. The rhigolene is obtained by distilling the gasolene a second time. The crude oil remaining in the naphtha stills is then pumped into stills heated by direct fires underneath, and having a capacity of about 1,000 gallons. This charge is distilled to coke which remains in the still, to uncondensable gases which pass into the atmosphere, and to liquid oils which are condensed and separated, according to their density, into No. 1, crude burning oil; No. 2, intermediate oil; and No. 3, crude lubricating oil. Each of these numbers is again distilled by itself in apparatus of the same size as that used for the first distillation, and the distillate from each is again separated, as before, into lighter, intermediate, and heavy oils. No. 1 from this second distillation is thoroughly agitated with strong sulphuric acid, and then with solution of caustic soda. It is then redistilled, and yields from the still about 80 per cent, of finished kerosene and mineral sperm, and nearly 20 per cent, of dense oils. No. 2 is redistilled before treatment with acid and alkali, and yields principally crude lubricating oil.

No. 3 is treated with sulphuric acid and then redistilled with caustic soda in the still. The dense paraffine oil that collects in the receiver is placed in wooden barrels in ice houses, where it remains for. from seven to ten days, during which the paraffine wax crystallizes so that the mass retains the form of the barrel. The crude paraffine is put into strong cloth bags, which are piled with iron plates between them upon the bed of a powerful hydraulic press, and subjected to very heavy pressure. The crude paraffine is crystallized repeatedly from solution in naphtha until it is perfectly pure and white. (See Paraffine.) The heavy oil is treated by the patent deodorizing process. This consists in carefully heating the oil in stills by fires placed underneath, and at the same time injecting steam, which is superheated by being passed through a coil contained within the still and covered by the heated oil. By this means 20 or 30 per cent, of the contents of the still is separated, and that which remains in the still when cooled is ready for sale as neutral lubricating oil. The highly colored last distillates that accumulate from all of these distillations are called "cokings," and yield when distilled by themselves crude lubricating oil.

The products of this establishment for 1873 were: naphtha (all grades), 300,000 galls.; kerosene, 1,250,000; mineral sperm, 250,000; neutral lubricating oil, 600,000; paraffine wax, 500,000 lbs. These amounts, large as they are, bear no comparison to the enormous quantities handled by some of the refiners nearer the oil regions, where the object sought is the largest possible production of kerosene. Of these the " Standard Oil Company" of Cleveland, O., and New York city, is the best example. The only articles produced by this company are the different grades of naphtha, kerosene, and paraffine lubricating oils. Their works and apparatus are adapted to cracking the crude oil and treating the distillates in quantities estimated by millions of gallons. They manufactured during the year 1873 of naphthas (all grades), 12,-424,006 galls.; kerosene, 68,518,424; paraffine lubricating oil, 1,540,716. Of this enormous' production 77 per cent, is kerosene, which is sent to all parts of the world. - A modification of this method of conducting the business has been adopted in a few instances. The crude kerosene is distilled at or very near the wells. The petroleum is cracked, and the naphthas and residuum are either used as fuel or sold to manufacturers of gasolene and paraffine oils.

The crude distillate is shipped in glued barrels to New York, and there treated. In this way freight is saved on all the impurities of the oil, and also on the light and heavy products which at best are worth no more than cost. There is also a further saving of loss by leakage, caused by the water acting on the glue with which the barrels are lined. The distillate is treated where it can be done cheapest and with least expense for transporting chemicals. An establishment at Hunter's Point, L. I., had a capacity for treating 700 bbls. of distillate daily, which was received from several distilleries in the oil regions. The entire product was exported. - No manufactured articles put upon the market vary more in quality than the products obtained from petroleum, especially kerosene. While new applications are constantly being found in the arts for the various grades of naphtha, still the purposes for which it can be used are comparatively few. Vast quantities of it have been burned under stills, and in some localities have been thrown away or sold at the purchaser's price. As a result, refiners of oil constantly labor under the temptation to throw the largest possible amount into the illuminating oil.

If the only effect resulting from such a course was the increased rapidity with which the oil burned, and the consequent reduction in its value, the evil might be borne; but to this must be added the fact that to this cause may be traced all those calamities which follow explosions of kerosene lamps. Frequent and dreadful as these disasters are, it is with great difficulty that the public can be convinced that all grades of naphtha and all fluids containing them, when burned in any kind of lamp (explosive or non-explosive), are more dangerous than gunpowder, because so much more carelessly used. These inflammable and, under certain circumstances, terribly explosive fluids, are nearly worthless as articles of commerce, and they burn so rapidly that they are of comparatively little value to the consumer as materials for illumination. No more than 5 per cent, will render kerosene inflammable at all ordinary temperatures, and liable to produce an explosion at any time when the vapors become mingled with air in proper proportion. These properties that render naphtha dangerous are inherent in the constitution of the substance itself, and no human art can change them.

Yet there are those who pretend to invent non-explosive naphtha stoves and lamps, a thing that never was and never can be invented; there are those who manufacture and sell kerosene containing naphtha, "and others who purchase the two, mix them, and sell them. The victims are generally women and helpless children. Good kerosene is always safe under all conditions attending its use. It is naphtha that injures the quality of kerosene, and naphtha is never safe under any circumstances. So alarmingly frequent have these accidents become, and so disastrous have been the results, that in all civilized countries very stringent laws have been enacted, restraining and regulating the sale and storage of petroleum and its products. Nearly every state in the Union has passed similar laws, and in many sections of the country kerosene may be purchased with comparative safety, as the different kinds of naphtha are regarded as dangerous, and are sold under proper restrictions. Yet notwithstanding these laws, and the general recognition of the fact that poor oils are very unsafe, a great deal of bad kerosene is burned every year, particularly in our large cities, and at the same time much property is destroyed and many lives are lost.

All lamps are safe with good oil, and the quality of any oil can be ascertained easily by the following test: Take a pint tin cup, till it nearly full of water warmed so that a thermometer immersed in it will show 120°, pour a small quantity of oil on the water, stir a little, then pass a lighted match quickly but closely over the surface of the oil once; if it ignites, the oil is unsafe. If purchases are made of from three to five gallons at a time, and this test is made, people can protect themselves.