New Electric Force.

Hokitika Guardian, 19 July 1921, Page 3

New Electric Force.

LONDON, May 31

A new electrical force, by which infinitely small electric currents are able to perform work out' of all proportion t« their magnitude, was described yesterday evening to a crowded gathering of the Institution of Electrical Engineers by Mr Alfred Johnsen and Mr Knud Rahbek, who had been invited to come to London to repeat the remarkable experiments they have recently made in Copenhagen.

Th P story of the valve which has revolutionised wireless telephony is wellknown to-day—how it picks tip the minutest electric currents and makes i,t possible to magnify them into sounds which reproduce the voice of a speaker thousands of miles awn} The Danish engineers have' made a more remarkable discovery than this. Currents still more feeble can not only be detected hut can be made to do aotuail work, such as to actuate a telegraph relay or Morse printer or enormously to magnify the voice. It is no exaggeration to sav that thennew relay makes it possible to have a portable wireless receiving set little bigger 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.

THE NEW POWER. A 41 ate cylinder, for instance, is slowly irevolved 1 with a metal band round it. 'As soon as a current passes through the two, thc cylinder is sloplied dead or the band held tight. A heavy lithographic stone was picked up by a brass disc only two inches in diameter when a current of extreme feebleness passed through it—so feeble that it made no difference even when the current |Kissed first through (he body of one of thc lecturers. What this means in practice is that a few thousand extra miles would make little or no difference in sending a wireless message. The rate of receivng wreless telegraph messages can be speeded up to several hundred words a minute, and so forth. The possibilities of the discovery when fully investigated will undoubtedly lead to fresh advances in many branches of commercial electricity. The new power, says Mr Thorne Biker generated by current so small is to be' hitherto negligible, strikes one as the nearest approach yet seen to the unsolvable problem of perpetual motion.