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Societies and Academies

Nature volume 100, pages 338340 (27 December 1917) | Download Citation

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Abstract

LONDON. Royal Society, December 13.—Sir J. J. Thomson, president, in the chair.—Prof. B. Moore: The formation of nitrites from nitrates in aqueous solution by the action of sunlight and the assimilation of the nitrites by green leaves in sunlight. Dilute solutions of nitrates exposed either to sunlight or to a source of light rich in light-energy of short wave-length (such as light from mercury vapour arc enclosed in silica) undergo conversion of nitrate into nitrite. There is an uptake of chemical energy in this reaction transformed from light-energy, as in the formation of organic carbon compounds in foliage leaves; it is to be added to the relatively small number of endothermic reactions induced by light. When green leaves are immersed in nitrate solution comparatively little nitrite accumulates, indicating that nitrites are rapidly absorbed by the green leaf. Nitrates taken up by plants from soil would, in presence of sunlight, be changed to nitrites, which are much more reactive than nitrates. This indicates that the early stages of synthesis of nitrogenous compounds are carried out in the green leaf and aided by sunlight. Rain-water collected for a considerable time contains no nitrites, all having been oxidised to nitrates, but if exposed to bright sunlight or ultra-violet light for a few hours a strong reaction for nitrites is always obtained. There is no hydrogen peroxide or ozone in air at surface level. The fresh odour in open air, commonly referred to as “ozone,” is probably nitrogen trioxide, which at high dilutions has the odour of ozone. The oxides of nitrogen are probably formed by the action of sunlight, rich in ultra-violet rays, in upper regions of the atmosphere upon air and aqueous vapour.—T. R. Moir: The transition from rostro-carinate flint implements to the tongued-shaped implements of river-terrace gravels. Seven flint implements, exhibiting a beak-like profile, have been found, associated with early palteolithSj in certain ancient valley gravels. The implements described exhibit certain characteristics of form only before seen in the rostro-carinates discovered beneath the Pliocene Red Crag and in other pre-Palasolithic deposits in East Anglia. They show also by the nature of their flaking and provenance that thev are of early Palaeolithic age. The dual character of thfese specimens is verv marked and points to the conclusion that the knowledge of the manner in which to make a palasolith was acquired by long experience in producing rostro-carinates. This view finds support in the experiments in flint-flaking which have been carried out. The specimens have been recovered from a wide area in southern England, and it seems reasonable to regard them as presenting transitional types linking the rostro-carinates with the earliest pateoliths.

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https://doi.org/10.1038/100338b0

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