ORIGIN OF X-RAYS

Otago Daily Times, Issue 18760, 13 January 1923, Page 7

ORIGIN OF X-RAYS

MANCHESTER DISCOVERY. At a, meeting of the Manchester Literary and Philosophical Society Mr William Thomson, oi Manchester, presented the society with some phosphorescent metallic sulphides, contained in four tubes, which, ho claimed, led ultimately to the discovery of X-rays by Profeasor Rontgen. The tubes, Mr Thomson explained, were fixed on a wooden stand arranged so that a high-tension electric current could be passed through the four at the same time, which had the effect of making the sulphides glow brilliantly in different colours. This frame and the tubes, Mr Thomson said, he had found in a cupboard in his laboratory some months ago, where they had lain for the last 45 years. During 1575 he had been interested in the wonderful beauty of the colours and brilliancy of certain metallic sulphides first brought to notice by Becquerol, of Paris. He made experiments with them, and in January, 1877, read a. paper before that society exhibiting the very tubes which he now presented to them. At the time he was impressed with the idea that some important discovery could bo made through the study of the light emanating from the sulphides, but he was unable to devote the necessary time to the subject. The same year, however, he wrote to Hr William Crookes (afterwards Sir William Crookes), who was then working, on lugh vacua, suggesting that it would be interesting to study tho sulphides in the high vacua he was then ablo to produce. A few days later, Mr Thomson said, Sir William Crookes came to Manchester, when he showed him the vacuum tubes he had produced, which glowed brilliantly under tho electric current, and gave him some of those sulphides with which Sir William afterwards made his classical researches on radiant matter. Subsequently tubes containing sulphides in high vacua were reproduced by philosophical instrument makers and sold as “Crookes’s Tubes.” And it was while exhibiting ono of these tubes that Professor Rontgen accidentally discovered that the rays from it, which were now known as X-rays, penetrated what we regarded as opaque bodies. Some yearn ago, Mr Thomson said, he received a letter from Sir William Crookes, in which ho expressed the opinion that when the history of the Rontgen Rays came to be published, tho part which Mr Thomson had taken in it would be duly acknowledged. Concluding, Mr Thomson said that he considered he was justified in claiming for Manchester and the Manchester Literary and Philosophical Society that the first step toward the discovery of the X-ray was taken in this city by him inducing Sir William Crookes to turn his attention to those sulphides which led to hie researches on radiant matter, the second step; while the third was the discovery by Rontgen that the rays passed through bodies which were opaque to ordinary light.