Abstract
LONDON Physical Society, May 11.—E. G. Richardson: The amplitude of sound waves in resonators. After a consideration of the relations between the ‘pipe’ and the ‘Helmholtz resonator,’ graphs of the variation of amplitude, obtained by means of a hot-wire anemometer traversed through various types of resonator, are reproduced. By means of a calibrated manometer of the vibrating membrane type, some direct values of the impedance of orifices are obtained. Traverses across an orifice through which the air is vibrating in simple harmonic form are obtained with the hot wire: these show a tendency for the air to vibrate with greater amplitude in annuli remote from the centre of the orifice.—R. E. Clay: The focus of a gas-filled X-ray tube. Pinhole photographs of the focus obtained with various radii of curvature of the cathode and various distances from the anticathode are discussed; it is concluded that with the tubes of the type considered, a radius of about 2 cm. and a distance of 3 or 4 cm. are the best conditions.
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Societies and Academies. Nature 121, 926–927 (1928). https://doi.org/10.1038/121926a0
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DOI: https://doi.org/10.1038/121926a0