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Royal Irish Academy, June 26. F. D. GREEVES: An investigation on the penetrating radiation from potassium. Measurements of the absorption of the?-radiation from potassium chloride by use of a Geiger tube counter. The value obtained by M¼hlhoff was confirmed with a different geometrical arrangement. The background of cosmic and local radiation was found to vary with weather conditions, being less intense during rain. H. O'NEILL HENCKEN and H. L. Movius: The cemetery cairn at Knockast, Co. Westmeath. In August and September 1932, the first Harvard Arch¦ological Mission in Ireland, under the direction of Dr. H. O'Neill Hencken, assistant curator of European arch¦ology in the Peabody Museum of Harvard University, excavated at Coolatore, Co. Westmeath, a large cemetery cairn of the Bronze Age. This contained in all 44 burials of which 4 were skeletons and the remainder cremations. Unlike most such grave-mounds, this contained no central burial with ‘secondary interment's grouped about it, but an unprecedented number of graves scattered through it. From the pottery, bronze knives, etc., found with the burials, it was evident that they covered a considerable part of the Bronze Age from about 1500 B.C. to somewhat after 1000 B.C. The human remains have been studied by Mr. H. L. Movius of Harvard. He has found that the skeletons conform on the whole to the general type of Irish Bronze Age skeletons, but believes that the cremating people probably belonged to a different physical type. J. DOYLE and W. T. SAXTON: Contributions to the life-history of Fitzroya. Fitzroya is an interesting link between the cupressinean and callitrinean conifers. It possesses an apical archegonial complex with a pollen tube directed to the top of the prothallus. The tube grows early and invaginates the prothallus deeply while the latter is still vacuolate. The pro-embryo is variable and the variations are discussed. They seem to be derivatives of two types of early pro-embryo, a four-celled pro-embryo completely filling the archegonium and one with four cells occupying a considerable part of the archegonium with a fifth free nucleus in the upper part. The mature pro-embryo commonly fills the archegonium and is fully septate. J. J. NOLAN and P. J. NOLAN: Further observations on atmospheric ionisation at Glencree. In a survey of more than four year's observations, it is shown that the control exercised by the condensation nuclei on the equilibrium of ionisation is very weak. Certain diurnal variations in the ionisation are found and the question of a diurnal variation in the rate of ion production is examined. R. W. DITCHBURN and Miss C. J. POWER-STEELE: Notes on resolving power (2). The resolving power with a microphotometer. The paper describes experiments on the resolving power of an optical system (for example, telescope or spectrograph) when photographic methods are used. The effect on the resolution produced by exposure, time and other factors is examined. The resolving power of lines of different intensity ratio is investigated. An increase of resolution is obtained by stopping out the central portion of the aperture. A new ‘characteristic’ is suggested for use in connexion with the deflection microphotometer. R. W. DITCHBURN: Notes on resolving power (3). The resolving power of the method of focal isolation. The paper discusses the resolving power and the geometrical optics of the method of focal isolation (see R. W. Wood: “Physical Optics". Second edition, p. 414). The relation of this method to the Christiansen filter is considered.
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Societies and Academies. Nature 132, 362–364 (1933). https://doi.org/10.1038/132362a0
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DOI: https://doi.org/10.1038/132362a0