- A compound gas; supports all life on the earth.
- Sometimes called the “Atmosphere” or envelope of the earth.
- May be pure or impure, but can be controlled.
- The most important of the elements.
We cannot see the air, but we can feel it when it moves against the body; then we say that there is a breeze or a draught or a wind. We breathe the air in and out, and though there is nothing to be seen, we know that it exists. If we try to stop the breath for a little, we are soon left in no doubt as to the need for air. The air is a mixture of gases, and the most important one is oxygen. This gas is the giver of life and energy, tonic and stimulating. Pure oxygen would be too powerful and would drive us on too fast. So the gas nitrogen prevents this, and “puts on the brake” to prevent us living too rapidly. When a person is very tired or is suffering from shock after an injury or an operation, a little extra oxygen may be given to restore the flagging energy. Without air one cannot live. Experiments have shown this. All animal and vegetable life is nourished by the air.
As one rises above the surface of the earth, the air becomes thinner and lighter. The breath becomes rapid and there is a sense of discomfort, and the lungs struggle to get the oxygen that the body requires. Climbers in the mountains of the Himalayas, or flying man rising to great altitudes must carry extra oxygen in cylinders, or have “pressurized” compartments in their planes. At a greater height, the air practically disappears, and we talk of “space,” and say that interespellar space, the vast area between the stars, is filled by the ether. We can see the moon and the stars through powerful telescopes, and men are planning to go there, but we do not know whether they have an atmosphere or air that would support human life.
The air on a hilltop or by the sea is pure and bracing. There are no germs of disease in the air over the sea. The air of a city street contains countless impurities. There is extra carbonic acid gas or carbon dioxide, breathed out from the lungs of men and animals. There is carbon monoxide from the engines of motor cars and from domestic fires, a very dangerous gas unless in very small quantities. Then there is every kind of emanation from decaying matter, for the air gives its hospitality to every kind of gas given off in that way.
Our life is regulated by the air. If there were no air, or a lighter or heavier form of air, there might be a different kind of life. Today Russia and U.S.A. are engaged in a race to be the first to reach the moon and they have succeeded a lot in that. Our knowledge derived from the study of astronomers is trying to ascertain whether there is a form of air around the moon that will support human life. The human race is increasing in numbers so rapidly that overcrowded nations are wondering whether the moon or any suitable planet, might have living conditions that would make suitable colony to drain off some of their superfluous populations. The first consideration will be, “Is their air to breathe?” And if the answer to that is in the negative, man’s bold effort to penetrate into other worlds is foredoomed to fail.