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The Department of Scientific and Industrial Research has just issued, through H.M. Stationery Office, a volume of its special reports on the mineral resources of Great Britain. It deals with the geological relations, nature and uses, and mineral, chemical and physical properties of ball clays, that is to say, of those plastic "transported" clays which, when fired in an oxidising atmosphere to the temperature of certain pottery ovens approximately 1,150 deg.-1,200 deg. C.-have a white or nearly white colour. They are formed by the decomposition of felspathic rocks, by natural agencies. In this decomposition, silicates such as the felspars break down, and the products ultimately undergo hydration with the formation of the hydrated silicate of aluminium, kaolinite, and, in many cases, mixtures of hydrated oxides. Where these products are found resting in the parent rock, the clays are termed residual; where they have been transported and deposited elsewhere, they are known as transported clays. The china clays of Cornwall are typical examples of the former; the ball clays discussed in this memoir are characteristic examples of the latter. Dr. Alex Scott
Sir Courtauld Thomson, chairman of the Limmer and Trinidad Lake Asphalt Company, in his speech at the annual general meeting in March, referred to the attention the company’s staff was paying to the problem of vibration, and the writers, who have worked in collaboration with the company’s staff, are now able to reproduce some results of experiments recently carried out. W.P. Digby and R.B. Fairthorne
A correspondent of "The Times" gave recently some exceedingly interesting details of some of the great Colonial water power developments in hand or under contemplation. These include schemes of hydro-electric power which are being carried out in tropical countries. Apart from the £6,000,000 Shannon project, which stands in a different category, the harnessing of the River Jordan below Lake Tiberias, the approaching completion of the Niger River storage dam, and the offer of tenders for the Pangani River works in Tanganyika illustrate the general demand for cheap and efficient power. The great Mandi scheme in the Himalayas will cost £4,000,000, and produce a maximum of 38,000 kilowatts.