GROWTH OF X-RAYS.

Waikato Times, Volume 114, Issue 19010, 29 July 1933, Page 6

GROWTH OF X-RAYS.

MODEL ENGINEERS' SOCIETY,.

There was a large attendance at : the monthly meeting of the Waikato Society of Model and Experimental Engineers last night, Mr J. Treloar presiding. A feature was an* interest- { ing address on x-rays, given by Dr. H. Harris, of Hamilton. The lecturer traced the growth (oft x-rays from the early experiments of j Faraday, between 1821 and 1867, to Hertz, who conducted valuable experi- ; ( ments with - electrio phenomena in ) vacuum tubes, and Roentgen, who ykt discovered the peculiar radiation pos---* sessing remarkable properties while experimenting with a highly-exhausted Crooke’s tube. The speaker stated that these rays were projected from a target of platinum, iridium, or tungsten, within the tube, against which the rays from the cathode were directed, and were found to differ from any form- of radiation hitherto known. They passed readily through many substances opaque to light'; they acted on an ordinary photographic plate; and they \yere incapable of rejection,. refraction or polarisation. They produced brilliant fluorescence on certain substances, and rendered the air a conductor of electrioity, and were capable of causing painful trouble on the human skin if it was -too long exposed to the rays. Demonstration Given. The speaker showed many different types of tubes, from the early Geissler tube to the latest water-cooled .tubes which have superseded all other types. 7 The lecturer gave an exhibition with his portable plant in operation, and showed the human hand througn the fluorescent screen.. The lecture proved one of the outstanding lectures delivered to the society. Mr Hope Johnstone gave a practical demonstration tff building a model turbine out of odds and ends. .This was the second of Mr Hope Johnstone’s interesting sei’ies of talks oh workshop practice.