NEW ELECTRIC FORCE

Dominion, Volume 14, Issue 265, 3 August 1921, Page 5

NEW ELECTRIC FORCE

NEAREST PERPETUAL MOTION. A new electrical force, by which infinitely small electric currents are able to perform work out of all proportion to their magnitude, was described recently to a crowded gathering of the Institution of Electrical Engineers by Mr. Alfred Johnsen and Mr. Knud Rahbek, who had been invited to London to repeat the remarkable experiments they have recently made "in Copenhagen. The story of the valve which has revolutionised wireless telegraphy is well known to-day—how it picks up the minutest electric currents and makes it possible to magnify them into sounds which reproduce tho voice of a speaker thousands of miles away. The Danish engineers have made a more remarkable discovery than this. Currents still more feeble can not only be detected, but can be made to do actual work, such as to actuate a telegraph relay or Morse printer, or enormously to magnify the voice. It is no exaggeration to say that their new relay makes it possible to have a portable wireless receiving set little biggey than a fountain pen. . , The discovery is of the simplest character. It is that certain minerals, such as slate or agate, when in contact with a piece of metal, stick together with intense firmness when even an excessively minute electric current passes through them. A slate cylinder, for instance, is slowly revolved with a metal hand round it. As soon as a current passes through 4the two the cylinder is stopped dead or the band held tiaht. A heavy lithographic stene was picked up by a brass disc only two inches in diameter when a current of extreme feebleness passed through if—so feeble that it made no difference even when the current passed first through tho body of one of the lecturers. What this means in practice is flint a few thousand extra miles would make little or no difference in sending a wireless message. The rate of receiving wireless telegraph messages enn he speeded up to several hundred words a minute, and so forth. The possibilities of the discovery when fully investigated will undoubtedly• load to fresh advances in many branches of commercial electricity. The new power, says Mr. Thorne Baker, generated by current so small as to h° hitherto negligible, strikes one as the nearest approach yet seen to tho insolv-»ble problem of perpetual motion.