Abstract
DUBLIN. Royal Dublin Society, June 27.—Prof. T. Johnson in the chair.—Prof. G. H. Carpenter: Injurious insects and other animals observed in Ireland during the year 1910. The points of interest in this paper are the record of a second brood of the codling moth (Carpocapsa pomonella) in the south-west of Ireland, and the occurrence of the maggots of Scaptomyza flaveola and an unknown Cecido-myid on turnips in county Louth.—Prof. J. Joly and L. B. Smyth: The radium-emanation content of soil gases and its escape into the atmosphere. The emanation content of soil gas is measured by filling a suitably calibrated electroscope with gas drawn from certain depths in the soil. The rate of its escape at the surface of the soil is investigated by means of a collector, which covers a certain area of the soil, and beneath which a slow current of air circulates. The air current is finally led through a charcoal absorption tube. It is believed that natural conditions are best realised by this collector. It is found that the conditions favouring the maximum rate of exhalation are dryness and openness of the capillaries of the soil. These conditions also lead to a fall in the emanation-content beneath. In accordance with this, the daily readings of emanation-content and of exhalation at the surface when plotted show opposing curvatures. The amount escaping at the surface is very considerable. The rate of escape is often more than sufficient to account for the decay of the emanation in a radio-actively homogeneous atmosphere extending to a height of 5 kilometres, and possessing an emanation-content equal to the average found by Eve and others. Soil within the city of Dublin is found to contain less emanation and exhale less than soils in the suburbs.. To the south of the city the soil is specially rich, the quantity of contained emanation near the surface per litre being such as would be in equilibrium with_ a quantity of radium of the order to-9 gram, the quantity exhaled per square metre per hour being also of this order. The causes influencing the quantity of radium emanation in the soil are under investigation, as well as the influence of the emanation upon vegetable life.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 87, 101–102 (1911). https://doi.org/10.1038/087101b0
Issue Date:
DOI: https://doi.org/10.1038/087101b0