LIGHTNING BOMBS.

Auckland Star, Volume LXIV, Issue 83, 8 April 1933, Page 7

LIGHTNING BOMBS.

ATOM UNDER FIRE.

625 MILES A SECOND.

LORD RUTHERFORD'S EXPERIMENTS.

Members of the Royal Institution were shown particles of hydrogen and helium being passed through 20,000 volts during full-scale experiments conducted by Lord Rutherford in the course of the first of his series of ■ lectures on the "Detection and Production of Swift Particles."

Lord Rutherford spoke of the use of the swift particles in bombarding the atom and the consequent importance of developing methods of all kinds for the production of such swift particles. There had been interesting developments in the photographing of these particles, he said, and in the study of their effects when they passed through matter, and there was great promise of still further interesting results. Amazing Velocities. After outlining the methods of producing swift particles, Lord Rutherford dealt with their velocities. A hydrogen particle passed through 1000 volte would reach a speed of 440 kilometres a second; if it were accelerated through a million volts its speed wpuld be 13,900 kilometres per second. Lord Rutherford then proceeded to demonstrate hydrogen particles passing through 20,000 volts within a glass tube. They were moving at a speed of 1000 kilometres a second. "The electrons," explained Lord Rutherford, "are generated by the impact of the positively-charged particles, which are generated in the tube. These positive ions have the capacity, when they strike the cathode rays, of generating electrons. The particles, however, are not allowed to go unimpeded through the gas. There is going on throughout the gas a steady recombination of one partiole with another, and you have a great variety of conditions that will determine the speed at which the particles arrive at the cathode." Rehearsal Failure. After outlining the pioneering work done in this field, throughout the years by Wien in 1898, and by Goldstein and J. J. Thomson, Lord Rutherford came to his most important experiment —the production of a parabola by means of defleeting the rushing streams of particles. Hydrogen and helium particles were introduced into a voltage of 20,000, and in the apparatus were magnetic and electric fields, which bent, or deflected, the stream of particles in different directions. The result was strikingly demonstrated on a phosphorescent screen, where in tho darkened lecture room the two green parabolas could be seen.

This experiment is not easy to perform, Lord Rutherford said, and he confessed that at a rehearsal before the lecture it had not been successful, but he was exceedingly pleased with the results now obtained. It was the first time he had demonstrated this experiment at the Royal Institution.