Verulam

In dealing with the development of science and technology, historians are interested in identifying original idea5 or concepts and their subsequent diffusion and elaboration as well as in biographical information on famous scientists and engineers. From Samuel Smiles to L T. C. Rolt the biographical tradition has been a popular and powerful influence on the history of technology. This approach has tended to produce history on the heroic scale with little emphasis on the development and interchange of ideas or the continuity of technological change. On the other hand, an economic historian might well view certain aspects of the Industrial Revolution without more than a mention of those engineers responsible for particular technological developments. For example, one could view the history of the steam engine in terms of the number of units produced, their geographical distribution and resulting influence on the expansion of the factory system. This paper, however, is concerned with the ideas and leading engineers behind the development of the modern suspension bridge. E.L. Kemp

Mr. D. R. R. Dick (Past President): In 1940, when the Ministry of Works requisitioned Queen Anne's Mansions for the Admiralty, I was the structural engineer heading up the team resgonsible for maintenance in Central London. The maintenance surveyor asked me to go along there and give some guidance as to their structural soundness. I was therefore responsible for the figures that you quoted concerning floor loads and strengths-but I did not do them in kilonewtons!

The term 'permissible stress' used in CP 1 14 describes a number that is defined by that Code and that, when used in formulae specified therein, defines a limit to the recommended service load for the element under consideration. It does not purport to correspond to the actual stress expected to occur in the element when subjected to the deduced value of service load, and any detailed consideration of the means by which this number was selected should show that it cannot be expected to do so in a material as complex as reinforced concrete. A.J. Tanner