Science: Magnetized Cold

When a piece of iron or other substance is magnetized, the molecules yank one way. When the substance is demagnetized the molecules jerk helter-skelter. The magnetic yanking causes molecular friction and produces an appreciable amount of heat which Professor Wrilliam F. Giauque, University of California chemist, used last week to reach the lowest degree of cold yet attained by man.

The temperature which Professor Giauque was trying for was Absolute Zero or 459.4° below zero Fahrenheit. Investigators had almost reached that point before by compressing helium gas and drawing off the heat of compression. This procedure brought them to — 451.84° F. when the helium gas turned liquid, to —457.6° F. when liquid helium turned solid. By compression and rapid cooling evaporation Professor William Hendrik Keesom of the University of Leyden last year reduced solid helium to —458.142° F. That seemed the ultimate, for Absolute Zero is theoretically unattainable.

In his strike at cold. Professor Giauque used gadolinium sulfate octahydrate, a colorless crystal substance derived from a rare earth metal. This he cooled to about —306.4° F., when he began wrenching the molecules with a huge magnet which University of California owns. Liquid helium absorbed and withdrew the magnetically generated heat. At —459.1° Professor Giauque was stopped, regretting that he could not stride the stupendously difficult little step of .3° which would carry him to Absolute Zero where substances should retain no more heat, where molecular activity should completely cease. where all things should be coldly inert. But Absolute Zero must be unattainable on earth except in a perfect vacuum, for where there is substance there must be heat absorbed from radiations of the Sun or other stars.