METALS THAT LIVE FOR SECONDS

Hawke's Bay Herald-Tribune, Issue 148, 10 July 1937, Page 11

METALS THAT LIVE FOR SECONDS

Radioactivity's Second Life

-yyHEN PBOFESSOB FEEMI lately rovealed the existence of new radio-aetive elementa more massive than uranium, it was as if an astronomer had found new planets beyond Pluto. Till then uranlum had been the coping-stone of the Table of the Ninetytwo Elements, with nothing beyond it, says E. S. Crew in the London Observer. The Italian physieist's experiments showed that even uranium could be made to give 'birth to elements lying beyond it. It as the latest development of the science of radioaclivity which was established by Madame Curie 's discovery of radium, and to which, forty years after, her daughter, Madame Curie Joliot, has given a new direetion. ( ^ Forty years ago the foundations of . the elements seemed to be rockdng. Madame Curie had disclosed one which* was not unchanging, but whose whole life was one of change. It would last thousands of years, but in the ehd its life would close, and radium, as radium, would cease to be, its life force all expended In giving out energy. „ Other elements were shown to be like it and when towards the end of her own life Madame Curie wrote the history of radioaetivity it had been shown that no element was invulnerable to change. The . dream of the alchemists that one element might be changed Into another was true. The whole structure of fact -and theory about the atom was built about her single discovery, but even when she might , have thought to yrrite "Finis" to the yolume of her-life-work, the building was being serapped, and its parts employed to raise another edifice. The strangest thing about this, the newer radioaetivity, is that the architeet should be Madame Curie 's own daughter.

One of the canons of the older radioaetivity was that it was spontaneous, unalterable by any agency that could' be brought to bear on it. Eadium ahd tho other naturally oceurring Tadioactive elements like thorium, aetinium, or uranium, would decay Iu their own time, giving rise to further deeaying elements eaeh with dts own prescribed time-table. Nothing could hasten or delay ihe .schednle. What was to be would be." ' As inquiry was "enlarged it. beeapie evident that most of all- -the elements - resembled .the conspicuously xadioaetive ones in breaking down, bnt tlieir docks were set to unalterable time intervals. Madame Curie had lighte'd a c'andle, still burning, to show dark plaees never before explored in the atom.* A new

line of inquiry opened when (tord). Rutherford began to bombard the. atom# of gases and the lighter elements with fragments collected from radium ?s explosions. The atoms were transmuted# The new alehemy foflnd practitioners all over the world, seeking and findingin the atom new missiles for its destruc^ tion. Very shortly another bxanch tef transmutation arose, for it was shoyra that hardly any elemont was a fixed immutable thing. , It could hardly be said to possess a freehold of its own? but had withan it* self, other elements, leaseholders, which* were liko it, but were different in thqir atomic structure. They were its im* tropes. Oue element has as many/ as fourteen. Still, the old radium. theory held th# field. - Elements and their isotropes could be prised apart. New radioactive elements sprang ffom the old, but it was all in the course of nafcute. Then, three years ago, the scene changed. JWhile Madame Curie Joliot and Kbr husband were following np Some %xperimental bombardments of boron. and aluminium, they observed that "•"after , they. had ceased fire the atoms- bom4 barded- continned to shOot off some . o£ their more elusive partieles. In the moment of that discovery the new radioaetivity was born. The oio* ments bombarded had been stiiTed to #- foreign radioaetivity. That property was no longer an exclueive natural propensity. It could be artifieittlly; imr planted. . The old idea. of an unalterable rate/of decay went by thd board; and 'soon/ all the world was again. bntey in improwing; on it. Every, sort of missile at errery -rate of velocity was hurled at th/e ©lo* ments, and the last two years hawe been marked by the shifting of the , attack from the lighter elements to the/heavier cnes. . ' .

-As a result -forty new. element# have . been brought to light. They are all radioactive varieties of the original elements, iron, manganese, Iwsmuth, zine^ etc., from whieh they are gqt out, though that exprefssion may give a wrong impression, because the founda-i tion of the new method is that the" neutron adds something to the element; it assails. Fermi, for example, slowed'. down th© neutrons with whieh he bom-»-bUTded uraiiium so that-they shoaild join. up more effeerively in a sorl of peacefull penetration. New instruiiients are- being; devised, in some way. TesemBling lenses;, to eoncentrate * the missil es. Tlie lives of ihe new elements, though real, - are ; generally brief. TEe longest lived last only a few days, some have a life measured cmly in seconds. Use has been found for one of them as a radium subistitute. But their real ,vala§* Is that of giving. birth to a new ideaof the elements^ and the processes by * which they are built tip and ©stab* lished. - .•* J , •-* '•