Probably the first man who went to a spring for a drink and found oil floating on the water was decidedly annoyed. He did not care in the least where the oil came from or what it was good for; he was thirsty, and it had spoiled his drink, and that was enough for him. We know now that oil comes chiefly from strata of coarse sandstone, but we are not quite sure how it happened to be there. The sand which formed these strata was deposited by water ages and ages ago—we are certain of that. Another thing that we are certain of is that where the strata lie flat, there is no oil. Hot substances become smaller as they cool; and as the earth grew cooler, it became smaller. The crust of the earth wrinkled as the skin of an apple does when it dries. In the tops of these great sandstone wrinkles there is often gas; and below the gas is the place where oil is found. There is no use in looking for petroleum where the folds of the strata are very sharp, because in that case the strata crack and let the oil flow away. It is not in pools, but the porous stone holds it just as a sponge holds water. If you drop a little oil upon a stone even much less porous than sandstone, it will not be easy to wipe it off, because some of it will have sunk into the stone.

In many places the gas forces its way out, and is piped to carry to houses for light and heat. Not far above Niagara Falls there was a spring of gas which flowed for years. An iron pipe was put down, and when the gas was lighted, the flame shot up three or four feet. The gas came with such force that a handkerchief put over the end of the pipe would not burn, though the flame would blaze away above it. In the country of the fire worshipers, on the shores of the Caspian Sea, fires of natural gas have been burning for ages, kindled, perhaps, by lightning centuries ago. There is a vast supply of oil in this place; and indeed there is hardly a country that has not more or less of it.

In the United States the colonists soon learned that there was petroleum in what is now the State of New York; but New York was a long way from the Atlantic seaboard in those days, and they went on contentedly burning candles or sperm whale oil, or, a little later, a rather dangerous liquid which was known as "fluid." The Indians believed that the oil which appeared in the springs was a good medicine. They threw their blankets upon the water, and when these had become saturated with the oil, they wrung them out and sold the oil. Those were the times when if a medicine only tasted and smelled bad enough, people never doubted that it would cure all their diseases, and they gladly bought the oil of the Indians.

When at last it became clear to the members of an enterprising company that oil for use in lamps could be made from petroleum, they secured some land in Pennsylvania that seemed promising and set to work to dig a well. But the more they dug, the more the loose dirt fell in upon them. Fortunately for the company, the superintendent had brains, and he thought out a way to get the better of the crumbling soil. He simply drove down an iron pipe to the sandstone which contained the oil, and set his borer at work within the pipe. One morning he found that the oil had gushed in nearly to the top of the well. He had "struck oil."

This was about ten years after the rush to California for gold, and now that this cheaper and quicker method of making a well had been invented, there was almost as much of a rush to Pennsylvania for oil. With every penny that they could beg or borrow, people from the East hurried to the westward to buy or lease a piece of land in the hope of making their fortunes. A song of the day had for its refrain,—

In the course of a year or two, the first "gusher" was discovered. The workmen had drilled down some four or five hundred feet and were working away peacefully, when a furious stream of oil burst forth which hurled the tools high up into the air. Hundreds of barrels gushed out every day, and soon other gushers were discovered. The most famous one in the world is at Lakeview, California. For months it produced fifty thousand barrels of oil a day, and threw it up three hundred and fifty feet into the air in a black column, spraying the country with oil for a mile around. The oil flowed away in a river, and for a time no one could plan any way to stop it or store it. At last, however, a mammoth tank was built around the well and made firm with stones and bags of earth. This was soon full of oil; and with all this vast weight of oil pressing down upon it, the stream could not rise more than a few feet above the surface. Just why oil should come out with such force, the geologists are not quite certain; but it is thought to result from a pressure of gas upon the sandstone containing it. The flow almost always becomes less and less, and after a time the most generous well has to be pumped.

A CALIFORNIA OIL FIELD A CALIFORNIA OIL FIELD
For scenery, one should not go to an oil field. Looks, smell, and oil alike are unpleasant, but every oil derrick covers a fortune and helps to make our machinery run smoothly.

An "oil field" may extend over thousands of square miles; but within this field there are always "pools"; that is, certain smaller fields, where oil is found. When a man thinks there is oil in a certain spot, sometimes he buys the land if he is able; but oftener he gets permission of the owner to bore a well, agreeing to pay him a royalty; that is, a certain percentage of all the oil that is produced. When this has been arranged, he builds his derrick. This consists of four strong upright beams firmly held together by crossbeams. It stands directly over the place where the well is to be dug. It is from thirty to eighty feet in height, according to the depth at which it is hoped to find oil. There must also be an engine house to provide the power for drilling. An iron pipe eight or ten inches in diameter is driven down through the soil until it comes to rock. Now the regular drilling begins. At the top of the derrick is a pulley. Over the pulley passes a stout rope to which the heavy drilling tools—the "string of tools," as they are called—are fastened. The drilling goes on day and night. The drill makes the hole, and the sand pump sucks out the water and loose bits of stone. When the drill has gone to the bottom of the strata which carry water, the sides of the bore are cased to keep the water out; then the drilling continues, but now the drill makes its way into the oil-bearing sandstone.

There is nothing certain about the search for oil. In some places it is near the surface, in others it is perhaps three or four thousand feet down. The well may prove to be a gusher and pour out hundreds of thousands of gallons a day; or the oil may refuse to rise to the surface and have to be pumped out even at the first. Naturally, no one is prepared for a gusher, and millions of gallons have often flowed away before any arrangements could be made for storing the oil. Sometimes a well that gives only a moderate flow can be made to yield generously by exploding a heavy charge of dynamite at the bottom, to break up the rock and, it is always hoped, to open some new oil-holding crevice that the drill has not reached.

Crude petroleum is a dark, disagreeable, bad-smelling liquid; and before it can be of much use, it must be refined. For several years it was carried in barrels from the oil fields to Pittsburgh by wagon and boat, a slow, expensive process, and generally unsatisfactory to all but the teamsters. Then came the railroads. They provided iron tanks in the shape of a cylinder fastened to freight cars, much like those employed to-day. There was only one difficulty about sending oil by rail, and that was that it still had to be hauled by team to the railroad, sometimes a number of miles. At length, some one said to himself, "Why cannot we simply run a pipe directly from the well to the railroad?" This was done. Pumping engines were put in a few miles apart, and the invention was a success in the eyes of all but the teamsters. In spite of their opposition, however, pipe-lines increased.

Before this it had been necessary to build the refineries as near the oil regions as possible in order to save the expense of carrying the oil; but now they could be built wherever it was most convenient. To-day oil can be brought at a small expense from west of the Mississippi River to the Atlantic seaboard, refined, and distributed throughout that part of the country, or loaded into "tankers,"—that is, steamships containing strong tanks of steel,—and so taken across the ocean. The pipes are made of iron and are six or eight inches or more in diameter. In using them one difficulty was found which has been overcome in an ingenious fashion. Sometimes they become choked by the impurities of the oil and the flow is lessened. Then a "go-devil" is put into them. This is shaped like a cartridge, is about three feet in length, composed of springs and plates of iron and so flexible that it can turn around a corner. It is so made that as it slips down the current of oil, it whirls around and in so doing its nose of sharp blades scrapes the pipes clean.

The pipes go over hills and through swamps. They cross rivers sometimes by means of bridges, and sometimes they are anchored to the bed of the stream. If they have to go through a salt marsh, they are laid in concrete to preserve the iron. If these lines were suddenly destroyed and oil had to be carried in the old way, kerosene would become an expensive luxury.

Getting the oil out of the ground and carried to the refineries is not all of the business by any means. The early oils crusted on the lamp wicks, their smell was unendurable, and they were given to exploding. Evidently, if oil was to be used for lighting, it must be improved, and the first step was to distil it. To distil anything means to boil it and collect the vapor. If you hold a piece of cold earthenware in the steam of a teakettle, water will collect on it. This is distilled water, and is purer than that in the kettle. Petroleum was at first distilled in a rough way; but now it is done with the utmost care and exactness. The crude oil is pumped into boilers holding six hundred barrels or more. The fires are started, and the oil soon begins to turn into vapor. This vapor passes through coils of pipe or long, straight, parallel pipes. Cold water is pumped over these pipes, the vapor turns into a liquid again, and we have kerosene oil.

This is the outline of the process, but it is a small part of the actual work in all its details. Kerosene oil is only one of the many substances found in petroleum. Fortunately, some of these substances are light, like gasoline and benzine; some, like kerosene, are heavier; and paraffin and tar are heaviest of all. There are also gases, which pass off first and are saved to help keep the furnace going. Then come the others, one by one, according to their weight. The stillman keeps close watch, and when the color and appearance of the distillate changes, he turns it off into another tank. This process is called "fractional distillation," and the various products are called "fractions." No two kinds of petroleum and no two oil wells are just alike, and it needs a skillful man to manage either.

Even after all this distillation, the kerosene still chars the wick somewhat—which prevents the wick from drawing up the oil properly—and it still has a disagreeable smell. To fit it for burning in lamps, it must be treated with sulphuric acid, which carries away some of the impurities, and then with caustic soda, which carries away others. Before it can be put on the market, it is examined to see whether it is of the proper color. Then come three important tests. The first is to see that it is of the proper weight. If it is too heavy, it will not burn freely enough; if it is too light, then there is too much of the lighter oils in it for safety. The second test is the "flash test." The object of this is to see how hot the oil must be before it gives off a vapor which will burn. The third, the "burning test," is to discover how hot the oil must be before it will take fire and burn on the surface. Most civilized countries make definite laws forbidding the sale of kerosene oil that is not up to a standard of safety. Oil for use in lamps should have an open flash test of at least 100° F. and a burning point of not less than 125° F.

We say that we burn oil in our lamps, but what we really do is to heat the oil until it gives off gas, and then we burn the gas. To keep the flame regular and help on the burning, we use a chimney on the lamp. The hot air rises in the chimney and the cold air underneath rushes in to take its place and brings oxygen to the flame. In a close, stuffy room no lamp will give a good clear light, because there is not oxygen enough for its flame. Let in fresh air, and the light will be brighter. If you hold a cold plate in the flame before the chimney is put on, soot or carbon will be deposited. A lamp gives light because these particles of carbon become so hot that they glow. In lamps using a "mantle," there is the glow not only of these particles, but also of the mantle. In a wax candle, we light the wick, its heat melts the wax and carries it to the flame. When the wax is made hot enough, it becomes gas, and we burn the gas, not the wax. Wax alone will melt, but not take fire even if a burning match is held to it. The reason is that the match does not give heat enough to turn the wax into gas. But put a bit of wax upon a bed of burning coals, where there is a good supply of heat, and it will turn into gas and burn.

The products made from petroleum are as different in their character and uses as paraffin and naphtha. Some of them are used for oiling machinery; tar is used for dyes; naphtha dissolves resin to use in varnish; benzine is the great cleanser of clothes, printers' types, and almost everything else; gasoline runs automobiles, motors, and many sorts of engines; paraffin makes candles, seals jelly glasses, covers the heads of matches so that they are no longer spoiled by being wet, and makes the ever-useful "waxed paper"; printers' ink and waterproof roofing-paper both owe a debt to petroleum. Even in medicine, though a little petroleum is no longer looked upon as a cure-all, vaseline, one of its products, is of great value. It can be mixed with drugs without changing their character, and it does not become rancid. For these reasons, salves and other ointments can be mixed with it and preserved for years.