NEWS BY MAIL.

Hokitika Guardian, 17 May 1927, Page 4

NEWS BY MAIL.

SPEED OF HELIUM. LONDON, -March 23

“ Don’t break that tube,” said Sir Freest Rutherford to bis assistant, when speaking at the Royal Institution on Saturday. “Jf you do, this loom will not he able to lie used for radioactive experiments for a long period—perhaps forty years.”

file lecturer’s subject was ‘.‘The Alpha Rays and Their Application to Atomic Structure.” Of the various types of radiation emitted during the transformation of radium and other radio-active bodies, the alpha rays, he said, are the most important. They consist of a stream of positively charged particles of helium which are spontaneously ejected with a speed of about 10.000 miles a second. From one milligram of radium about 10,000,000 of these particles are expelled each second. When these particles come to rest they become atoms of the rare gas helium, and it seems probable that the greater part of the helium found in the earth is due to alpha particles of radio-active bodies which have lost their charge. The alpha particles have the greatest energy of motion • of any particles known to science. When they are absorbed by matter, heat is evolved corresponding to the kinetic energy, and the constant and rapid evolution of heat from radium is due to this bombardment of matter by ‘alpha particles. The study of the alpha particles had thrown much light on the structure of me atom. The deflection of the alpha particles as the result of a close collision with an atom of matter first gave us definite information on the nuclear structure of the atom, and had allowed us to determine the magnitude of the charge on their minute nucleus for different element);. The bombardment of elements by the swiftest alpha particles showed in a definite way that the nuclei of a number of atoms could he broken up in an intense collision with an alpha particle. By special amplifiers the small currents due to the ionisation of the alpha particle wore magnified about a million times and shown by a gnlvabomotcr.

HOAXING A TOWN. LAUSANNE, April 1. This town was badly hoaxed to-day by a local newspaper which in its issue this morning announced in thick type that an American millionaire, described as ‘Alar-car Touch,” who was staled to he a famous rifle shot and a man greatly admired by the Swiss Army, had recently, while in Lausnime, endowed a club with n valuable trophy to be shot for annually. The prize carried with it a free trip to the United States for two months. The first contest, it was added, bad been arranged to take place to-day at a bridge which spans the centre of the town, and some of the best shots in the country would fire at a mannequin placed on the weathervane of the cathedral. 400 yards distant. All possibility of accident bad been eliminated, stated the journal, the trajectory of the projectiles having been carefully calculated beforehand.

When the offices and shops closed at noon, thousands of workers thronged the bridge, but seeing nothing abnormal suddenly remembered that it was the Ist. of April.