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The Minister of Transport has caused a circular to be issued to all highway authorities in Great Britain drawing attention to the provision of the Bridges Act, 1929. The main provisions of this Act are designed to facilitate the procedure for the reconstruction of weak bridges in private ownership, e.g., in the ownership of railway companies, canal companies, etc. Many of these bridges, as is well known, are not fitted to carry modern traffic, and the restrictions which their owners are authorised by law to impose on their use by heavy vehicles have caused considerable inconvenience and loss to trade and industry.
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