Abstract
LONDON. Physical Society, October 24.—Prof. C. H. Lees, president, in the chair.—Dr. N. W. McLachlan: The effect of pressure and temperature on a meter for measuring the rate of flow of a gas. The theory of an instrument for measuring the rate of flow of a gas is outlined, the effects of variation in the temperature and pressure of the gas being taken into consideration. This theory is tested experimentally for pressures varying from 1250 to 250 mm. Hg, and for temperatures from 10° C. to 100° C. It is found to be fairly accurate. The results are applied to the measurement of the rate of flow of gas on an aeroplane in the upper atmosphere, where a reduction in temperature and pressure is encountered. It is shown that the instrument reading for a certain N.T.P. volume of gas depends on the altitude, but that this volume can be obtained by using a correction factor.—Capt. J. H. Shaxby: A cheap and simple microbalance. The instrument, devised for bacteriological use, had to be cheap and moderately robust. It consists of a long horizontal fibre joining the lower ends of two vertical beams, each pivoted very little above its centre of mass. A small weight acting at the middle of the fibre thus causes a considerable depression. This is read off by arranging a slider on a vertical millimetre scale about 2 ft. in front, so that the middle of the fibre and a second short fibre placed just behind it are in line with a “peephole” on the slider. Adjustment is provided for quickly and largely altering the sensitiveness. The deflections are converted to masses by the use of calibrating weights. The apparatus is built up from a “Meccano” set.—J. W. T. Walsh: The resolution of a curve into a number of exponential coniponents. The paper gives a method for the resolution of a curve of the compound exponential form B= ∑na1e- λ1t into its components, the values of a and λ for the n different exponential terms being found from 2n values of B equidistant, along the axis, of t. A method is also given for finding the most probable values of these constants, from any number (>2n) of observed values of B taken at irregular intervals of t.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 104, 325–327 (1919). https://doi.org/10.1038/104325a0
Issue Date:
DOI: https://doi.org/10.1038/104325a0