Presidential address delivered November I, 1900 / by Dr. John Macintyre.

  • Macintyre, John.
Date:
[1900]
Catalogue details

Licence: In copyright

Credit: Presidential address delivered November I, 1900 / by Dr. John Macintyre. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    molecules on the anticathode. Continuous work over a prolonged period has been secured in even such an arrangement as the Wehnelt by a form supplied by De Mare, for which it is claimed we can now almost work for an indefinite period owing to automatic circu- latory arrangements for cooling. The vibrating string interrupter and Hirschmann's turbine have each lately been employed and recommended with advantage in particular work. The risk involved with tubes in the present day is so great that many have sought refuge in the excellent mercury jet interrupter of Levy, and another rotating form by Mr. MacKenzie Davidson, to whom we owe so much. His ingenious and admirable interrupter, only the other day placed in our hands, promises to give great and good results. The question of the tube, to my mind, however, as far as apparatus is concerned, is the most important. No doubt many of our difficulties, in the deep-seated structures of the body, arise from that irregular refrac- tion or dispersion which the rays suffer as they pass through the tissues. Nevertheless, we have seen by the experiments of Mr. Campbell Swinton that, even when the vacuum remains the same, we can cause variations in tubes by comparatively simple methods, and this has been taken advantage of by Dr. Dawson Turner. I am quite aware that there is scarcely a part of the tube which has not been submitted to the most careful scrutiny, that endless experiments have been made, especially in the highly refractive substances and dense materials used as anticathodes, also in cooling arrangements by Levy and Grunmach. No doubt these have furthered our work. Notwithstanding all, however, and great im- provement in intensifying screens—which of course we really desire to dispense with if possible—we have not