a fire is started in the furnace underneath, and the firing is kept up steadily until the run is completed. The vapor passes over into the worm of the condenser, a large tank kept full of cold water, and is condensed. At the end of the condenser is the running box, where the specific gravity of the distillate is tested, and where it is turned into the receiving tanks. It is here that the separation of the distillate into the different grades of benzine, standard, water-white, etc., is made by shifting the steam at the running box into the lines which lead to the respective tanks, when the desired degree of gravity is reached.

From the receiving tanks the carbon oil distillates are pumped into the" agitator," a large iron tank with a cone-shaped bottom, into which a strong blast of oil is carried from a double-acting air-pump or "blower." The distillate is first freed from any water which may be held in suspension; it is then "treated" with about two per cent. by weight, of sulphuric acid. The treatment consists in thoroughly mixing the acid with the oil by means of the air blast, which is delivered upward from the bottom of the agitator. This removes any particles of fixed carbon or other solid matters, and also removes, to a great extent, the yellow color and disagreeable odor of the distillate. The agitation is continued until a sample taken in a test-glass shows that the "sludge” formed by the acid will settle quickly to the bottom of the glass, leaving the oil clear at the top. The blower is then stopped and the "sludge" allowed to settle in the cone-shaped bottom of the agitator, from which it is then run into a spent-acid tank. It is better to draw out a little of the oil than to leave any of the acid in. The oil is then thoroughly washed with large quantity of water until the water drawn off below shows no acid reaction. It is then treated with either a solution of causticsoda or with aqua-ammonia, to remove any remaining trace of acid, and render the oil clear and bright. No excess of alkali should be allowed to remain in the oil. If the "treatment" has been properly conducted, the oil is ready for shipment when it leaves the agitator, although it is usually allowed to stand a short time in what used to be called the " bleacher," before it is shipped.

a

In the early days of refining, the whole run from the still was made into one grade of burning oil. It was soon discovered that this contained a dangerous element, which rendered it unsafe for family use. Inspection laws were therefore passed requiring the oil to stand a prescribed fire test. The United States standard test was fixed at 110° Fahr., for the burning point, and a heavy tax, at one time as high as twenty cents per gallon, was placed upon it. After the removal of the tax, 110° test was considered the standard until the several states began to pass in spection laws requiring different tests. Finally, public opinion in most

of the states has fixed upon 150° Fahr. for the burning point, as practically safe. The standard for export, however, still remains at from 110° to 115° Fahr. In order to make the oil stand the government test (110°), it was necessary to "cut off" the first part of the run and turn it into a separate tank. In some cases this product was allowed to run to waste, there being no commercial demand for it, and its exceedingly volatile character making it both difficult and dangerous to keep it in store. Its value as fuel was soon discovered, and many refiners burned it under the stills. The readiness with which it could be converted into vapor, and the value of this vapor for heating and illuminating purposes, soon led to the invention of the vapor cooking-stove, the gasoline streetlamp, and the gas-machine for private houses and factories. Having reached this point, it soon found its way into the retorts of the large gas companies as a substitute for coal. These several uses give the benzine or naptha series a commercial value equal, if not superior, to any other part of the "run" from the still. It is now carefully separated into different gravities, those destined for use in the gas-machine running from 85° to 90° B.; the grades intended for domestic use are deodorized, and have only one objectionable quality left, that is their inflammability.

By carefully excluding the benzine series at the first end of the run, and the crystallized paraffine at the other end, a distillate may be obtained which will, when properly treated, give a burning oil of 48° В., having an agreeable odor, white as pure spring-water, and which, at any temperature below 150° Fahr., will quench a burning taper. This is the " ne plus ultra" of the refiner, so far as a lamp-oil for family use is concerned, for it is not probable that a safer, better, cheaper or more agreeable home-light will ever be made from petroleum.

The refiners of Marietta and Parkersburg have never manufactured any products from that part of the "run" which lies between the burning-oil and residuum. The practice has usually been to cut the waterwhite distillate from the center of the run for 150° test, then to combine the two ends for 110° test; any distillate too heavy to go into the 110° oil is run back into the crude tank, and comes back into the still to be run over again. What remains in the still is drawn out and sold as residuum at about crude-oil price. Another plan is to stop the distillation when the oil in the still weighs from 27° to 30° B., allow it to cool and draw out and sell as reduced lubricating oil.

The neutral and paraffine oils have been neglected. Mr. George Rice, has, however, lately added to his plant in Marietta a filtering. house, and expects in future to give some attention to that class of products.

After the "run" is completed the residuum is drawn out, the still cooled down and the manhead is taken off; as soon as the temperature is endurable the men go into the still, scrape the coke from the bottom and clean it as thoroughly as possible; it is then refilled and started on another run. The average time made is about two runs each week; therefore, to find the weekly capacity of a refinery, its total still capacity is multiplied by two. This would make the present total capacity of the refineries at Marietta about 4,000 barrels crude per week.

The remainder of the work about a refinery consists in trimming, glueing and painting the barrels, filling and shipping the product. The crude oil, distillates and refined oils, are moved from one point to another, by the steam pump, and, from large works, much of the oil is shipped in bulk by tank cars. Oil for the southern markets is filled into tin cans of five gallons each, two of which are packed in a wooden case; this is known to the trade as case oil."

Marietta is favorably situated as a refining point for southern and western trade, and would probably refine a much larger portion of the crude oil produced in her immediate vicinity were it not for the powerful influence of the "Standard Oil Company," which carries the oil from her very doors to Parkersburg and Cleveland.

CHAPTER VII.

THE DRILLING AND CARE OF OIL WELLS.

BY FRED. H. NEWELL, E. Μ.

An oil-well, as the term is used in the eastern United States and Canada, is a small circular hole of comparatively great depth, drilled through the surface soils and into the underlying rock, for the purpose of obtaining crude petroleum. The diameter of the hole, when finished, averages less than six inches, and the depth ranges from a few hundred feet to three thousand. As a rule, there comes from an oil-well, besides the petroleum, inflammable gas and water, more or less saturated with salt. The earliest of these small deep wells were drilled for brine for salt manufacture, then later similar wells were drilled for oil, and now many are drilled for the gas, as in turn it has been utilized.

A description of the ordinary methods of drilling oil wells, which by far outnumber salt and gas-wells, is equally applicable to all three classes, and it may be said that the chief difference between salt, oil and gas wells pertains to the relative values of these products, so often occurring together.

This inflammable gas is often greatly compressed, and when the well penetrates to the rock in which it is stored, the gas rushes out with such violence as to throw out at intervals not only oil, if present, but even the heavy salt-water. From these points of resemblance to artesian wells, that is, the small diameter and great depth of hole, and the pouring out of fluid, these wells have been incorrectly described as artesian wells, but in the one case the flow of water is continuous and quiet, due to steady hydrostatic pressure, and in the other the flow is intermittent and violent, due to an expansion of gas originally under a pressure, sometimes greater than the hydrostatic pressure of that depth. Flowing wells, especially when little or no oil is present, have been termed "geysers," but differ from the true geyser in that the salt-water is thrown out, not by expansion of a part of the water into steam by heat, but by pressure of a compressed gas existing in the earth at normal temperatures.

Until within the last quarter of a century, the drilling of deep holes has been in all countries, excepting, perhaps, in China, an experiment, when money and time were lavishly expended on each well in devising tools and acquiring skill in handling them. Since the time of the first drilling for oil in 1859, these operations have grown to a great industry, with men skilled in each of its numerous subdivisions, and large establishments especially devoted to the manufacture of its peculiar tools. The single fact that nearly one hundred million dollars has been expended since 1860 in making these "holes in the ground," will testify to the importance of this branch of mining. The head-quarters of this business, from which are sent out machinery and trained men to all parts of the world to drill for oil and gas, for water, both salt and fresh, and for other minerals, are the oil regions of western Pennsylvania, which may be considered as overlapping into New York and Ohio.

Although the tools and ways of using them are by no means perfect, and each year sees some improvement, yet there are certain definite methods and shapes of tools which are in general use throughout the entire oil-regions, and which are accepted as the present standard of excellence. These have resulted from the trial and frequent failure of the innumerable inventions of ingenious oil-men. The requirements to which all these inventions have had to conform, besides that of fitness for their purposes, are that they shall possess strength and simplicity of parts, since the operations are carried on often in the least settled parts of the country, and the tools are subject to all the rough usage of frontier work. A description of the drilling of wells in the newly developed oil-fields of eastern Ohio, can then be but a review of the latest, and, therefore, best practice in deep-drilling throughout the cilregions. The most complete account of this, together with a description of machinery and tools is given in the excellent report of John F. Carll, of the Pennsylvania Second Geological Survey, published in 1880 (see Vol. III, page 285, etc). His descriptions have been largely used in the exhaustive report on petroleum, by S. F. Peckham, from the U. S. Census Office. (Report on the Production, Technology and Uses of Petroleum and its Products, by S. F. Peckham, Washington, 1885.)

Either of these works, supplemented by the finely illustrated catalogue of the Oil Well Supply Company (Bradford and Oil City, Pa.), issued in 1884, must give to any intelligent reader a clear conception of the ordinary processes. There have been few changes in the tools and ways of using them since Mr. Carll's report, and these have been mostly toward increase of strength and weight, and saving of labor.