The engineering genius of a Renaissance man

Stuart Nathan

Features Editor

The Science Museum's brilliant Leonardo da Vinci exhibition shows the 15th century polymath as the engineer he was and a man of his turbulent time, in a way we don't often appreciate

Leonardo's flying machines

© Science Museum, models © Archivio Museo Nazionale della Scienza e della Tecnologia Leonardo da Vinci – Alessandro Nassiri

Regular readers might remember that one of the more pleasant perks of working on The Engineer is the occasional invitation to previews of new exhibitions at the Science Museum which, for a proudly-confessed nerd like me, is like a greedy child being given the keys to the sweetshop. Which is why, on Tuesday morning, I was to be found in the museum’s basement, gazing literally open-mouthed at the fruits of the brain of Leonardo da Vinci.

The Science Museum is the latest venue for a touring exhibition originating with the French organisation for public science communication, Universcience, and Milan’s Museo della Scienza e della Tecnologia Leonardo da Vinci (MUST). Entitled 'Leonardo da Vinci: The Mechanics of Genius', it presents 39 models of the machines Leonardo designed, including flying machines, weapons and tools. In doing so, it presents a side of the archetypal Renaissance man that many people will not be familiar with, and one that engineers in particular will find fascinating.

Today, we think of Leonardo (as he’s invariably known; never call him da Vinci, especially if you’re within earshot of a Renaissance scholar) primarily as an artist. We know he was a polymath, and his anatomical studies are well-known (although even those are more often linked to their use as research for art than anything else). What becomes clear from the exhibition is that Leonardo was, possibly above all other things, an engineer. That was how he made his living: the princes who paid his salary might have commissioned the odd fresco from him, but it was his machines they were really after.

Living in 15^th century Italy, Leonardo’s world was one of city-states that were constantly at war with each other, and Leonardo spent a lot of his time compiling what we might see as prospectuses to show prospective employers what he could do for them in defending their own citizens and massacring those of their neighbours (you could easily draw parallels with the preoccupations of today’s politicians). An important part of these documents were designs for siege engines and weapons; and it’s clear that these were as much to terrify the enemy as anything else. One of the first objects in the exhibition is a huge crossbow, placed vertically and about three metres high. From Leonardo’s drawings, we can see this is a scale model: he intended the actual thing to be the height of a house, and its purpose was to fire flaming projectiles into the midst of the enemy. Leonardo’s letters often talk of the damage and great injury his designs could cause, but they also make a point of stressing the panic and terror they would inspire. Clearly Leonardo would have completely understood the deterrent theory of today’s nuclear states. You’d only have to see a house-sized crossbow once before you ran like hell.

Giant crossbow: Run away!

© Archivio Museo Nazionale della Scienza e della Tecnologia Leonardo da Vinci – Alessandro Nassiri

Leonardo didn’t build these machines; but what he did do was draw them. He drew everything. “Nobody drew machines like Leonardo; his designs have an incredible vivacity that still speaks to us today,” explained Martin Kemp, emeritus professor of the history of art at Oxford University, one of the world’s leading authorities on Leonardo and a guest at the exhibition viewing. It wasn’t just the way the machines looked on paper that was so revolutionary, Kemp added: it was the thinking and analysis behind them, and the methods Leonardo invented to depict them.

For Leonardo, invention began with observation. Aged 20, his first proper job was as an apprentice in a workshop on the enormous building site for Florence’s cathedral, the Duomo. We know that he was involved in the construction of a huge metal sphere that now sits on top of the cathedral’s crowning dome, but he would have been familiar with the machines on the site, such as the cranes that were being used to lift the dressed stones, designed by the artist/architect Brunelleschi. He observed them, and he drew them. "He visualised things, understood things and drew things in three dimensions, so they appear as solid objects,’ Kemp said. “but the point about that is that sometimes important parts of the mechanism would be hidden behind something closer to the observer. So Leonardo drew what he called elementi but we would think of as components: detailed diagrams of how the mechanisms worked and the parts they were made up from. Nobody had done that before.” What is now very familiar to us as an exploded diagram was pioneered by Leonardo.

Prof Martin Kemp pictured being interviewed at the opening of “Leonardo da Vinci: The Mechanics of Genius” exhibition. © Science Museum.

One of the things that marked Leonardo out was his curiosity. It’s clear that he sought out mathematicians, talked to them and read their texts, and his machines are based on a rigorous understanding of their underlying principles (or at least as rigorous as the science of the time allowed; Leonardo didn’t know much trigonometry, Kemp noted, because the Ancient Greek texts on the subject weren’t translated into Italian at the time.) He also experimented throughout his life, into phenomena such as the properties of materials and friction, using instruments he designed himself. The exhibition includes models of instruments he used in his investigations of his lifelong obsession with flight, including an anemometer consisting of a flexible flap that the wind would blow against a curved scale to indicate its speed, and a hygrometer, consisting of a balance that weighed a wax sphere against a piece of wadding of equal weight when dry, but which would become heavier as it absorbed moisture from the atmosphere. They are brilliant pieces of instrumentation engineering, and as curator Jim Bennet, an emeritus keeper at the Science Museum who worked on the exhibition pointed out, completely unprecedented.

Bennet worked on the Science Museum’s contribution to the exhibition: a series of small mechanical models produced in 1952 for an exhibition to mark the 500^th anniversary of Leonardo’s birth, which was staged at the Royal Academy and was the forerunner of the blockbuster art shows we know at the Academy today (if any of our readers remember this show, we’d love to hear from them). The other models in the exhibition were made for MUST, also in the 1950s; but the British ones, commissioned from a company in Wimbledon called Goacher Model Engineering, came first, Bennett said. He writes about them here. ‘We are claiming some primacy here,’ he said. Much smaller than the Italian models, the Goacher set is labelled ‘Leonardo for a time of austerity’, reflecting post-War Britain’s lack of funds.

The Science Museum’s Keeper Emeritus Jim Bennet © Science Museum.

The distinction we see between engineer and artist simply didn’t exist in Leonardo’s time, Bennet told me; our view of him today is coloured by the fact that the artwork survives whereas the machines didn’t. Never in charge of his own workshop, Leonardo would have known that most of his designs would never be built. There is no physical trace today of the completed engineering works that we do know of from his journals, such as a sluice that formed part of the defences of Venice; and the precious drawings were not known until relatively recently. Bennett thinks that it’s more a Victorian hangover than a modern view: art was seen as much higher status in the 19^th century, and engineering had the taint of ‘trade’ about it.

Martin Kemp said that Leonardo saw his role as being ‘a second Nature.’ “He looked at what was around him, understood it very often by drawing it, and then took the principles he had learned and used them to create something new. When he was designing a flying machine, he knew that you couldn’t copy feathers; you had to understand how they worked, how they created lift, and then devise something that did the same thing.” Kemp added that Leonardo knew full well that his ornithopter – a flying machine with flapping wings operated by a pilot pulling levers – would never fly because of the power-to-weight ratio; after 1500 he switched to designing hang-gliders, but even these incorporate a mechanism to spread the wing-tips to improve their flight characteristics.

By 1500, Leonardo had abandoned impractical ornithopters and switched to designing hang-gliders, but he still couldn't resist biomimimcry and mechanisms. © Archivio Museo Nazionale della Scienza e della Tecnologia Leonardo da Vinci – Alessandro Nassiri

Equally, some of the machines were just for show. The famous screw-aerofoil helicopter was a novelty designed as an entertainment (an important part of Leonardo’s role at court); equally, a self-propelled vehicle driven by the energy stored in crossbow-like components wasn’t a weapon, but was intended to carry the figures of gods in an elaborate court masque. Incidentally, this sort of thing was going on all over Europe; England’s own Renaissance prince, Henry VIII, employed Hans Holbein the Younger in a similar role (as well as painting stunning portraits, he designed salt cellars and stage sets).

Kemp’s description of Leonardo’s process has to be one of the most eloquent statements of an engineer’s job I’ve ever heard; and the exhibition shows it off to a fascinating extent. Who knew that Leonardo designed machine tools? Yet there’s a fully working mechanism that automates the production of files. Interested in ropes and fabrics? Here’s a machine to twist 15 cords into a rope, and a spinning wheel that anticipates designs from the 18^th century. Here are modern-looking bearings on a table for conducting friction experiments; and architectural designs based on the mathematics of budding flowers that wouldn’t be out of place, apart from their 15^th century ornamentation, on the Stirling Prize shortlist. A small section shows how some of Leonardo’s ideas on mimicking nature are being carried into the 21^st century; our old friend Festo’s robot seagull, which I last saw rapidly approaching my head, is displayed in skeletal form next to Leonardo’s ornithopter with its almost identical spars and levers.

Leonardo's file-cutting machine tool

© Archivio Museo Nazionale della Scienza e della Tecnologia Leonardo da Vinci – Alessandro Nassiri

Leonardo was a man out of time and yet completely of his time; a humblingly broad and restless intellect that couldn’t be pinned down in his own life and still can’t today. Bennet admitted that if there had been a line manager overseeing him, Leonardo would probably have driven him insane. “But contemporary accounts say he was a really nice man; easy to talk to and fun to be around. He was very witty and loved to talk.” We’ll never know for sure, of course. But if you want to get an idea, and see how much you have in common with this amazing man, I urge you to get along to the Science Museum before 4 September.

If I might be permitted a personal note, this week marks the birthdays of both of my late grandfathers. One was an artist, the other a talented mechanic. They would have loved this exhibition. So, Jacob Freedman and Jack Nathan, this article is for you both.