COLDER THAN THE POLE

Grey River Argus, 17 September 1941, Page 7

COLDER THAN THE POLE

(By Professor J. B. S. Haldane, Britain’s most eminent living Scientist)

British scientists led the way in the liquefaction of gases. One of the biggest steps was taken by Dewar, who invented tfie vacuum flask now sold under trade names such as Thermos. It consists of two layers of glass with a vacuum between them, and silvered like a mirror.

The vacuum is to prevent heat leaking in through air or other gas. The mirror is to prevent it crossing by radiation. It is one of the many laboratory inventions which have proved very useful in ordinary life, but it is mainly used to prevent heat leaking out of tea or soup, not to prevent it leaking into liquid air.

Air is a mixture of nitrogen, oxygen, and smaller amounts of other gases. When it is liquefied and heat allowed to leak in, it slowly evaporates like any other liquid. But as is usual in mixtures, some parts evaporate before others. This principle was first discovered in the case of mixtures of water and alcohol. If you boil beer, most of the alcohol comes off before the water, and if you condense the steam on something cold, you . get a liquid containing much more alcohol than the beer.

This, of course, is how whisky and other spirits are made. So don’t try the experiment, because if you do you will make a very second-rate whisky, and make yourself liable to a huge fine for having an illicit still. The fact that the same word, spirit, was used for alcohol and the vital principle which is supposed to leave a man when he dies, proves, by the way, how very materialistically our ancestors thought about life.

But to return to liquid air, if it is left standing, most of the nitrogen comes off first, and what is left behind is not very pure oxygen. This can be further purified, as alcohol can be redistilled; and much of the commercial oxygen used for cutting steel and treating illness is made in this way,

The Soviet Union is right ahead of the rest of the world in separating gas mixtures by this method. They have huge supplies of natural gas underground, and are determined to use it as carefully as possible. There are also supplies in the U.S.A, and Canada, but a large amount of them is wasted, for the capitalists who own them are interested in immediate profit, whilst good Socialists will not squander natural resources which cannot be replaced.

So there is a huge laboratory at Kharkov devoted to the study of all sorts of mixtures of liquid gases. The same mixture is kept at various different temperatures, and the gas which comes off it is analysed. In this way, the conditions for the best separation are worked out. This is the biggest laboratory of its kind in the world, so though Kharkov is a long way south of London, some, places in it are much colder than the .

North Pole. The coldest place in the world used to be an apparatus m a laboratory at Leyden, in Holland, where helium, the hardest of all gases to liquefy, was first liquefied and then frozen. But I do not know whether this laooratory is still working, or even whether it still exists.

In Moscow, Professor Kapitza has been working on the design of,gasliquefying apparatus, and he can now liquefy helium in a machine which will stand on a small table, whereas the necessary apparatus used to fill a large room.

The technical knowledge gained in these laboratories is being put to practical use. To take a single example, one might suppose that, because there is plenty of oil there, all the buses in the Caucasian oil fields would run on oil. But this is not so. The ground yields gas as well as oil, and oil is easier to transport than gas. So they are trying to use gas on the spot and send the oil away. Already some buses are being run on liquid methane, one of the gases in the mixture’which comes out of the ground.

We have plenty of methane in Britain, where we call it firedamp. In fact, thousands of tons of it go up into the air each day from the upcast shafts of our coalpits. It is doubtful whether any large fraction of it could be used even under Socialism, and quite certain that it will not be used under capitalism.

There, are three great advantages in storing a gas in the liquid fqpm rather than compressed. You can get much more of it into a given space, you do not need a thick container, and there is no danger of a cylinder bursting. Besides this, methane has a very great advantage over petrol as a motor fuel. If a mixture of air and petrol vapour is too highly compressed before it explodes, it explodes too sharply to give a steady push to the piston. This is called “knocking.” It can be remedied with anti-knocks such as lead tetraethyl. But mixtures of methane and air do not knock, even at a compression ratio of 16 to 1. This is a considerable advantage in small internal combustion engines.

On the other hand, as heat leaks into the container, the liquid gradually escapes as gas. So it must be used fairly quickly. For this reason, liquid gases are more suited to a planned Socialist economy than to a capitalist system where production and consumption are unorganised.

For you certainly can’t hoard liquid oxygen in the hope that its price will rise. So we can hardly expect that the possibilities of gas liquefaction will be at all fully used in British industry until Britain is a Socialist commonwealth. And then we shall have to go to the Soviet Union to learn the most up-to-date methods.