OXIDATION 



4437 



OXYGEN 



ing and social, meet at night. Many of the 

 most brilliant careers of English history began 

 in these clubs. Oxford life is designed to bring 

 the best culture of the ages to each man and 

 to help him cultivate his particular gifts, thus 

 assisting him in finding the place in life for 

 which he is best fitted. In normal years the 

 faculty numbers about 300, and the undergradu- 

 ate student body about 3,000, but during the 

 War of the Nations the number of undergradu- 

 ates fell below 1,000. 



Consult Corbin's An American at Oxford ; 

 Lang's Oxford. 



OXIDATION, ok si da' shun. When oxygen 

 combines with other substances so as to change 

 the character of the original substance or to 

 form entirely new compounds, the process is 

 called oxidation. It may be slow or fast. When 

 it is rapid and accompanied by heat and light, 

 it is called combustion, in which case the sub- 

 stance burns. Slow oxidation is one of the life 

 processes of the body. It is the gradual burn- 

 ing of the tissues of the body, thus keeping the 

 body warm and furnishing the energy for ac- 

 tion. The rusting of iron, too, is oxidation, the 

 rust being the red iron oxide formed. See 

 OXYGEN. 



OXYGEN, ok' si jen. The atmosphere is 

 composed of about one part oxygen to four 

 parts nitrogen, and the oxygen is the life-giving 

 substance. It is a gas which enables animals 

 to live and fire to burn. Because of its relation 

 to life oxygen is sometimes called vital air. It 

 is the most abundant simple substance or ele- 

 ment in existence. It constitutes one-fifth of 

 the atmosphere, about one-half by weight of 

 all the rocks, and eight-ninths by weight of 

 water. Oxygen is a little heavier than air, and 

 without color, odor or taste. One can easily 

 ire it in the laboratory for experimental 

 purposes, by heating in a closed retort a mix- 

 ture of potassium chlorate and black oxide of 

 manganese, and collecting the gas in inverted 

 jars over water. 



Experiments with Oxygen. The following 



simple and interesting experiments can easily 



be performed with oxygen. Since the gas is 



i' r than the air, it will remain for a short 



in a jar with cover of glass or cardboard. 



rover should be placed over the mouth of 



th- inverted jar containing the gas and the jar 



ttx n be lifted from its position over the water 



and set in place for the experiment. 



1 Attach a match to a wire. Light the match 

 nn.i place It In the Jar. Notice how much more 

 brightly It burns than In the air. 



2. Place burning sulphur in a jar of oxygen and 

 notice the bright flame produced. 



3. Dip the end of a wire or of an old watch 

 spring in sulphur. Light the sulphur and place 

 the wire in a jar of oxygen. The wire will burn 

 and throw off brilliant sparks. At the close of the 

 experiment the inside of the jar will be coated 

 with oxide of iron (iron rust). 



How Oxygen Supports Life. If an animal or 

 a plant is deprived of air it dies. By respira- 

 tion the air is drawn into the lungs; there it 

 gives up a part of its oxygen to the blood, by 

 which it is distributed to all parts of the body. 

 The oxygen unites with the tissues, or oxidizes 

 them, and in this way the heat is produced 

 which keeps the body at a uniform tempera- 

 ture. Among the waste products formed during 

 this process is carbon dioxide, which is expelled 

 from the system through the lungs. Oxygen 

 thus purifies the blood, and by a process of slow 

 combustion (oxidation) of the tissues supplies 

 the body with heat. 



Plants, on the other hand, take in a large 

 quantity of carbon dioxide through their leaves 

 and give off oxygen, but this action takes place 

 only under the influence of direct sunlight. 

 These two great kingdoms, the animal and the 

 vegetable, perform an important work towards 

 keeping the supply of oxygen in the air con- 

 stant. What the animal exhales the plant in- 

 hales, and what the plant exhales the animal 

 inhales. One should not infer, however, that 

 the proportion of oxygen in the atmosphere is 

 maintained wholly as a result of this relation 

 of the animal and vegetable kingdoms. 



Uses of Oxygen. Oxygen forms many com- 

 binations in nature, and without it many com- 

 mon processes would be impossible. Fires would 

 not burn, and many substances, such as iron and 

 steel, could not be produced; but the pure gas 

 was not until recently considered to be of any 

 practical use. Formerly it was supposed that, 

 if one should breathe pure oxygen, he would 

 burn his life out in a short time. We now know 

 that this is not a fact, and oxygen is frequently 

 used to restore a person who has been suffo- 

 cated, or one who is unable to obtain enough 

 air, as in cases of pneumonia, asthma and croup. 

 Divers now carry tanks filled with o\ynm un- 

 (! r pn->un . and without it the submarine could 

 remain under water only a short time. 



For commercial purposes oxygen is stored 

 imclrr -trong pressure in iron cylinders. When 

 1 with hydrogen in proportion of one part 

 hydrogen to two of oxygen and burned at the 

 mouth of a tube with a small aperture, it forms 

 an intensely hot flame. Under high pressure 



