Fairy stories and 'magical thinking' obscure origins of Crystal Palace and Eiffel Tower

I once refereed a promotion application that listed projects applying biological ideas to architecture. I discovered that many of the reports were taken from university press releases. Such reports tend to be ‘friendly,’ if not sycophantic. I realised they described what the projects hoped to achieve, and that the projects were to be done by third-year students. With such fairy stories you can easily concoct an account of a brilliant (imaginary) career. I rejected the application.

Fairy stories may be more common in areas where two or more disciplines are being mixed, where few people know enough, or are disbelieving enough, to realise that there is a gap to be bridged. 

One of the most robust fairy stories is that the ridge-and-valley roof of the Crystal Palace, designed by Joseph Paxton for the Great Exhibition of 1851, took its inspiration from the leaves of a waterlily, Victoria regia. This is apparently credible, since Paxton was one of the first to grow the plant in the UK. That is, until you look at the detail. The lily leaf is flat, floppy and floats, while the roof is corrugated and independently stiff. The ridge-and-valley structure was invented by the horticulturalist John Claudius Loudon to improve illumination in a glasshouse by the morning and evening sunlight meeting the glass roof at a right angle, while reflecting more of the hotter midday sunlight. Loudon showed this to Paxton in the late 1820s. Paxton experimented with the design and used it in the palace, claiming it as his own. 

Possible beginning

When did the waterlily leaf come into the story? After the success of the Crystal Palace, Paxton gave a presentation at the Royal Institution. He took a lily leaf with him, although we don’t know why. Perhaps it was press reporters who linked the leaf and the roof to produce their fairy story.

Was the Eiffel Tower inspired by the structure of the thigh bone? Georg Hermann von Meyer, a famous anatomist, showed the internal anatomy of the human femur to the engineer Karl Culmann, who recognised the similarities with the loadbearing design of a crane he was developing. This was in the 1860s, but the fairies said that the femur episode had presaged the design of the Eiffel Tower by some 40 years. Magical thinking. Gustave Eiffel innovatively used wind-tunnel experiments and calculation to design the eponymous tower, which is also an early example of structural hierarchy, combining efficiency and durability.

The Eastgate Centre in Harare, Zimbabwe, copied the thermosiphon model of temperature control of the termites’ nest, although it wasn’t passive since it needed fans to circulate the air. Measurement (eventually!) of the temperature of the termite nest showed it to be little different from that of the surrounding soil. It doesn’t have a thermosiphon system! It does have thermal mass, as does the Eastgate Centre. Ventilation of the termite nest, which is facilitated by diffusion activated by turbulence (rather like our lung), is less critical since insects can often cope with wide variations in temperature and the concentration of CO₂. 

Want the best engineering stories delivered straight to your inbox? The Professional Engineering newsletter gives you vital updates on the most cutting-edge engineering and exciting new job opportunities. To sign up, click here.

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.