Abstract
BY the will of Sir Charles Boys, provision was made for the foundation by the Physical Society of a memorial to one of its most distinguished past presidents, and the Council of the Society decided that it should be a prize to be awarded annually for experimental work either still in progress or completed not earlier than ten years before the date of the award. The first (1945) prize has been awarded to Dr. A. H. S. Holbourn, of the Clarendon Laboratory, Oxford, for his successful measurement of the angular momentum of circularly polarized light. Before this work, it was uncertain whether this momentum really was h/2π. Holbourn succeeded in suspending a half-wave plate on a ½a silica fibre and, working under good vacuum conditions, he was able to measure the torque produced when the direction of rotation of circularly polarized light was reversed in its passage through the plate; torques as small as 2 ×10—11 dyne cm. were measured with an accuracy of 3 per cent. Apart from its great theoretical significance, this experiment represents a most delicate piece of manipulative work comparable with Boys' construction of the radiomicrometer. It was described briefly in Nature (137, 31; 1936) and the Journal of Scientific Instruments (16, 331; 1939) and at greater length in a D.Phil, thesis (Oxford, 1938). Historically, it is interesting to note that the work was carried out in a compartment of the same cellar of the Old Clarendon Laboratory in which Boys himself measured the mean density of the earth. The presentation will be made at the meeting on December 12.
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Charles Vernon Boys Prize. Nature 156, 685 (1945). https://doi.org/10.1038/156685c0
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DOI: https://doi.org/10.1038/156685c0