There was never any intent for the new wind Code, BS 6399: Part 2, to increase wind loads above the values predicted by CP3: Ch.V Part 2² on average. Independent calibrations of the new Code confirm this has been achieved, yet BS 6399 is widely perceived as being more onerous than CP3. So why should this be? N.J. Cook
Dr L. J. Morris (F) (University of Manchester) I should like first to congratulate Dr Owens and Dr Moore on their presentations and the work they have done, highlighting difficulties and problems and how they were overcome.
The orb-web of Araneus diadematus exhibits three forms of hierarchy in its structural design: relative stifiess, prestress, and geometric stiffness. These experiments showed that all forms have the potential to influence the flow of internal forces through this natural tension structure, but relative stiffness is unquestionably the dominant factor. The lightness and eficiency of a spider web appear to be related to its structural hierarchy. L.H. Lin and Professor Dr-Ing. W. Sobek
Puzzles in trigonometry Aspects of triangles and circles continue to interest members. Dudley Dennington acknowledges that he is another in a long line of contributors, and writes from Surbiton in Surrey: In Verulam (l8 November 1997) your correspondents do not mention the set of right-angled triangles, which appears to be infinite, in which integral shorter sides differ by one. I have established this up to N = 15. The set is interesting in that, unlike the familiar ones which have been quoted, the triangles get marginally ‘steeper’ as the sides get longer rather than ‘flatter’, approaching an equilateral shape. As usual, 3:4:5 turns up.