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1、OilBy G.C. ThornleyThere are three main groups of oils: animal, vegetable, and mineral. Great quantities of animal oil come from whales, those enormous creatures of the sea which are the largest remaining animals in the world. To protect the whale from the cold of the Arctic seas, nature has provide
2、d it with a thick covering of fat called blubber. When the whale is killed, the blubber is stripped off and boiled down, either on board ship or on shore. It produces a great quantity of oil which can be made into food for human consumption. A few other creatures yield oil, but none so much as the w
3、hale.The livers of the cod and the halibut, two kinds of fish, yield nourishing oil.Both cod liver oil and halibut liver oil are given to sick children and other invalids who need certain vitamins. These oils may be bought at any chemists.Vegetable oil has been known from antiquity. No household can
4、 get on without it, for it is used in cooking. Perfumes may be made from the oils of certain flowers. Soaps are made from vegetable and animal oils.To the ordinary man, one kind of oil may be as important as another. But when the politician or the engineer refers to oil, he almost always means miner
5、al oil, the oil that drives tanks, aeroplanes and warship, motor-cars and diesel locomotives; the that is used to lubricate all kinds of machinery. This is the oil that has changed the life of the common man. When it is refined into petrol, it is used to drive the internal combustion engine. To it w
6、e owe the existence of the motor-car, which has replaced the private carriage drawn by the horse. To it we owe the possibility of flying. It has changed the methods of warfare on land and sea. This kind of oil comes out of the earth. Because it burns well, it is used as fuel and in some ways it is s
7、uperior to coal in this respect. Many big ship now burn oil instead of coal. Because it burns brightly, it is used for illumination countless homes are still illuminated with oil-burning lamps. Because it is very slippery, it is used for lubrication. Two metal surfaces rubbing together cause frictio
8、n and heat; but if they are separated by a thin film of oil, the friction and heat are reduced. No machine would work for long if it were not properly lubricated. The oil used for this purpose must be of the correct thickness; if it is too thin it will not give sufficient lubrication, and if it is t
9、oo thick it will not reach all parts that must be lubricated.The existence of oil wells has been known for a long time. Some of the Indians of North America used to collect and sell the oil from the wells of Pennsylvania. No one, however, seems to have realized the importance of this oil until it wa
10、s found that paraffin-oil could be made from it; this led to the development of the wells and to the making of enormous profits. When the internal combustion engine was invented, oil became of world-wide importance.What was the origin of the oil which now drives our motor-cars and aircraft? Scientis
11、ts are confident about the formation of coal, but they do not seem so sure when asked about oil. They think that the oil under the surface of the earth originated in the distant past, and was formed from living things in the sea. Countless billion of minute sea creatures and plants lived and sank to
12、 the sea bed. They were covered with huge deposit of mud, and by process of chemistry, pressure and temperature were changed through long ages into what we know as oil. For these creatures to become oil, it was necessary that they should be imprisoned between layers of rock for an enormous length of
13、 time. The statement that oil originated in the sea is confirmed by a glance at a map showing the chief oilfields of the world; very few of them are far distant from the oceans of today. In some places gas and oil come up to the surface of the sea from its bed. The rocks in which oil is found are of
14、 marine origin too. They are sedimentary rocks, rocks which were laid down by the action of water on the bed of the ocean. Almost always the remains of shells, and other proofs of sea life, are found close to the oil. A very common sedimentary rock is called shale, which is a soft rock and was obvio
15、usly formed by being deposited on the sea bed. And where there is shale there is likely to be oil.Geologists, scientists who study rocks, indicate the likely places to the oil drillers. In some cases oil comes out of the ground without drilling at all and has been used for hundreds of years. In the
16、island of Trinidad the oil is in the form of asphalt, a substance used for making roads. Sir Walter Raleigh visited the famous pitch lake of Trinidad in 1595; it is said to contain nine thousand million tons of asphalt. There are probably huge quantities of crude oil beneath the surface.The king of the oilfield is the driller .He is a very skilled man. Sometimes he sends his drill more than a mile into the earth. During the process of drilling , gas and oil at great pressure
