THE ABSOLUTE ZERO

Shannon News, 14 May 1926, Page 4

THE ABSOLUTE ZERO

490 DEGREES OF FROST. The late Professor Kammerlingli Onnes whose death has just taken place, was famous all over tho world for his . low-temperature ex* periments. Many years ago the lata Sir James Dewar succeeded in producing' liquid air, by liquifying- and solidifying the so-called "perman» ent" gases, hydrogen, nitrogen and oxygen, forcing them, step by step down the heat gradient until he reached the frigid temperature of 436 deg. - below the zero of the Fahrenheit scale (wjtrich Fahrenheit believed was the lowest temperature attainable).

There Sir James Dcwar was forced to stop, though the absolute zero was only 23deg. lower. The financial resources at his disposal at the Royal Institution" were inadequate to permit the costly experiments necessary to bridge the gulf. At this point the work was carried on by Professor Onnes, at Leyden University, where he set up a special laboratory for the purpose, and followed the methods of his British colleague. The ample endowments at his disposal at Leyden enabled him to attack the absolute zero in a way impossible to Sir James Dewar, and, working with the refractory gas, helium, he finally succeeded in converting it into the liquid state, which it changed into at the frigid temperature of 450 deg. below the Fahrenheit zero, or 482 deg.. of frost. For that spendid achievement he was awarded the Nobel Physics Prize, and then began a long series of experiments having for their object the attainment of the absolute zero, Odeg. below that of liquid . helium. In . that he all but succeeded, reaching 272.18 degrees below the zero (approximately 45Sdeg. below the Fahrenheit zero)., or by the English scale 490deg\ of frost, ldeg. from th e final goal. It was believed that at such an incredibly low temperature helium would be frozen into a solid, but it remained obstinately in the liquid, state. has yet to be frozen into a solid, unless it is the one exception to. all matter, and has no solid state. The small gap 'between the lowest temperature Professor Onnes attained, and the absoluto zero is only 0.82 of a Centigrade degree, but few laboratories have the expensive apparatus with which to conquer it. The work of .Sir James Dewar and Professor Onnes yielded much knowledge as to the properties of matter at very low temperatures, and especially as to the electrical conductivity of metals. Liquid air has many uses, liquid and solid hydrogen are working agents in scientific research everywhere, and medical science has found in liquid oxygen an invaluable handmaid. Sci- | ence has lightened and extended the activities of the working world in countless ways, and no one can say what practical results will follow the labours of the pioneers of low temperature. .:,f^-iiraran