PROCESS OF DISTILLATION.

227

condenser is a very light, volatile substance, called Gasoline, of a specific gravity of about 80° Baume. After this, and when the oil has reached a temperature of 212° Fahrenheit, the remainder of the water in the still will pass off in the form of steam, and be condensed as acid water. The product of the condenser is then benzine or naptha, from 80° down to 60°, when burning fluid begins to present itself; from 60° down to 38° the product is different grades of burning fluid, that are usually mixed, forming a light-colored oil when finished. Burning fluid, for economical and safe use in the household, should not be above a specific gravity of 46° Baume, and endure a "fire test" of 115° Fahrenheit, and not flash in the lamp when burning.

The product of the still under 38° is treated differently at different establishments. Sometimes it is distilled, and a further per centage of burning fluid extracted; sometimes it is used for lubricating purposes, and at still other establishments the paraffine is extracted.

The practice differs materially in different parts of the country, both as affected by the views of different distillers, and the comparative value of different products in the process. The practice is affected, too, somewhat by the character of the crude oil used. This differs in specific gravity from 38° to 50° Baume. The heavier oils, however, are seldom or never distilled, being more valuable for lubricating purposes. In some establishments the oil of the Allegheny and that of Oil creek are mixed, and in this way a compound of medium gravity is obtained that works most satisfactorily.

The gasoline and naptha are then turned over to be treated, by being steamed down to a proper degree of gravity, for other manufacturing purposes. The distil

late is now ready for the deodorizing process. It is placed in a treating tank of iron or wood, lined with lead, called an "agitator," where it is agitated with a paddlewheel, or, what is better, with a powerful wind blast, produced by the power of a steam engine. When this agitation resembles a miniature storm on the ocean, a portion of sulphuric acid, amounting to from three-fourths of one per centum to one and a half per centum, is added slowly, and the mass agitated from ten to thirty minutes, according to the views of the chemist. When the tank becomes quiet, and the mass settles, the impurities are drawn off from below, and one or more treatments made in like manner.

When sufficiently treated with acid, and the impurities removed, the treatment is resumed in the same manner with soda lye, or caustic soda dissolved in water. After being thoroughly agitated with this addition, and the further impurities withdrawn, lukewarm water is freely sprinkled upon the oil and allowed to run off, until the oil is found to be entirely free from impurities, when it is ready for market.

The acid cannot be again used in this process, but need not be lost. It may be digested with scraps of iron, and afterwards roasted and made into copperas. The alkali may be used again and again, until it parts with its caustic properties. This may be restored by the addition of quick lime, and finally may be made to act upon bones, producing phosphate of lime.

By way of contrast with the modern results of the refining process, the following extract of Professor Silliman's report, made in 1855, is appended:

"Three hundred and four grammes of crude oil,

SILLIMAN'S REPORT.

229

submitted to fractional distillation, in a linseed oil bath,

= 212° F. 66 at 140° C. to 150° C. at 150° C. to 160° C. at 160° C. to 170° C.

"Product No. 1, almost entirely water.

"Product No. 2, an oil perfectly colorless, very thin and limpid, but having an exceedingly persistent odor, &c. "Product No. 3, tinged slightly yellow, perfectly transparent, &c.

Product No. 4, more decidedly yellowish than the last, &c.

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

"Product No. 6. This with the two subsequent products, were each more highly colored and denser than the preceding. The last product had the color and consistency of honey, and the odor was less penetrating than that of the preceding oils.

The density of the several products of this distillation shows a progressive increase, thus:

"To form an idea of the density of these several products, it might 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."

In regard to the properties of this oil, Professor Silliman says: Exposed to the severest cold of the past winter, all the oils obtained in this distillation remained fluid. * * * The chemical examination of these oils showed that they were all composed of carbon and hydrogen, and probably have these elements in the same numerical relation. * * * 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; hydro-chloric, chromic and acetic acids do not affect it; litharge and other metalic acids do not change it or convert it in any degree to a drying oil; potassium remains in it unaffected, even at a high temperature; hydrate of potash, soda and lime are also without action upon it.

The oil is nearly insoluble in pure alcohol, not more than four or five per centum being dissolved by this agent. In ether the oil dissolves completely, and, on gentle heating, is left unchanged by the evaporization 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 dissolves 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 dissolves in it as it does in other oils."

Thus far Professor Silliman; but it must be remem

WANT OF A LUBRICATOR.

231 bered that the oil submitted to his examination was the thick, heavy substance collected by ditching and forming pits. The results would have been very different with the lighter oils of Oil creek, brought up from the depths below. Still the report is valuable, as showing the properties of the oil under the most unfavorable circumstances attending the examination.

CHAPTER XVIII.

LUBRICATORS.

WE come now to speak of petroleum as a lubricator. An unexceptional article of this kind was becoming one of the great wants of the age. With the multiplication of machinery, and the increase of business throughout the land and on the ocean, the want of an article adapted to all kinds of weather was exciting the inquiry of various classes of business men connected with railroads and manufactories everywhere.

Petroleum appears to answer the conditions of such an article better than any other substance yet discovered. It has natural characteristics that adapt it to the purpose, is found in exhaustless quantities, and is produced at comparatively low rates.

It has already been remarked that this oil is found with various degrees of densities. At Franklin, on French creek and Sugar creek it is sometimes found as great as 29°. This heavy oil is used almost exclusively