ARTIFICIAL COLD

New Zealand Herald, Volume LXXIII, Issue 22388, 7 April 1936, Page 14

ARTIFICIAL COLD

MARVELS OF SCIENCE

EXHIBITION IN LONDON LIQUID AND SOLID GASES [from our own correspondent] LONDON, March 14 Temperatures lower than those existing in Nature, lower even than .those in inter-stellar space, have been attained in the past few years in physical laboratories in England and abroad. With -the object of illustrating the principles underlying this modern branch of science and their utility, a special exhibition has been organised by the Science Museum, with the assistance of the scientific institutions and the industrial organisations concerned. The liquefaction and solidification of the gases in the atmosphere are the outcome of this low temperature research, by which temperatures considerably below those produced by normal mechanical refrigeration are obtained—with the production of solid helium in 1926 no gas remains which cannot be liquefied and solidified. More than three-quarters of the air is nitrogen, while about one-fifth is oxygen. The remainder consists of small quantities of argon, carbon dioxide, neon, helium, krypton and xenon. Hie last-named occurs only as about one part in 10,000,000 parts of air.

Results of Experiments The exhibits have been devised to show how these substances are obtained in the three states of gas, liquid and solid in the scientific laboratories and on an industrial scale, while particular attention has been paid to the illustration of their modern uses, many of which are now familiar to everyone.

Sir William Bragg, president of the Royal Society, opening the exhibition, said the endeavour to get down to absolute zero had proved to be far more than a sporting adventure. The very construction of the machinery required to reach very low temperatures had developed a new and most important technique. "And what of the results?" asked Sir William. "It is odd to see air liquefied and running like water, to see rubber lose all its spring and become as fragile as a piece of china; to see fruit powdered under a hammer and quicksilver made into a mallet. There are more fundamental effects which the scientist observes closely. And many will be deeply interested in the industrial applications. "Liquid oxygen is now produced in largo quantities, because it is easily transported. It is used in the production of those intensely hot flames with which metal workers now cut up steel sheets as the tailor cuts his cloth. When mixed with cotton it is a most useful explosive. It is used in welding and other metallurgical operations; in medicine, in mine rescue work, underwater work, and high altitude flying.

Strange Scientific Quest "Also the liquefaction of air has made it possible to extract from it its neon, argon, and other gases now widely used in the manufacture of electric lamps and tho gay advertisement signs of the streets. And, to sum up, very few scientific quests have been so strange in their beginning, their progress and their results." According to calculations, no lower temperature than minus 273.16 degrees Centigrade can be reached. Very near approaches to this havo been obtained, but it will never actually be reached. In the exhibition may be seen the machines for obtaining these very low temperatures, as well as demonstrations of the cutting and welding of steel with the oxy-acetylene flame. There is apparatus which shows how liquid air and liquid helium are made, and thermometers which respond to the touch of a finger tip. Investigators of this particular branch of science are not interested in any temperature above minus 110 degrees Centigrade.