Page:Popular Science Monthly Volume 82.djvu/525

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THE

POPULAR SCIENCE

MONTHLY

 

JUNE, 1913




SOME FURTHER APPLICATIONS OF THE METHOD OF POSITIVE RAYS[1]
Professor SIR J. J. THOMSON, O.M., LL.D. D.Sc, F.R.S.

CAVENDISH PROFESSOR OF EXPERIMENTAL PHYSICS, CAMBRIDGE, AND PROFESSOR OF NATURAL PHILOSOPHY, ROYAL INSTITUTION

THE method to which I shall refer this evening is the one I described in a lecture I gave here two years ago. The nature of the method may be understood from the diagram given in Fig. 1. A is a vessel containing the gases at a very low pressure; an electric discharge is sent through these gases, passing from the anode to the cathode C.

PSM V82 D525 Thomson demo of generating positively charged radiation.png

Fig. 1.

The positively electrified particles move with great velocity towards the cathode; some of them pass through a small hole in the center, and emerge on the other side as a fine pencil of positively electrified par-

  1. Address before the Royal Institution of Great Britain, Friday, January 17, 1913.