The secrets of Leonardo

THE SECRETS

OF

LEONARDO

CLAUDIA VIRGILIOACCESS TO MULTIMEDIA

This booklet is for educational usage and it is not printed for commercial purposes, art.70 I. C. C.Some images and contents are imported.

contents

Preface........................................................page 04

the self propelling cart.................page 06

the mechanical lion.........................page 09

the robot soldier...............................page 12

The secrets of Leonardo

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LPREFACE

This booklet covers the latest insights into the inventions of Leonardo di Ser Piero da Vinci (Leonardo son of Mr Piero from Vinci), the name in old

Italian of the scientist who is considered one the greatest genius in history: Leonardo da Vinci.

He was born in Italy 1452. He was the son of a lawyer, Piero, who lived in Vinci, a Tuscan hill town in the lower valley of the Arno River, about 40 km from Florence. Leonardo showed his ability in drawing at an early age, so his father asked an artist friend Andrea di Cione, known as Verrocchio, if his 14 year old son could become apprenticed in Verrocchio’s workshop.

This workshop, one of the finest in Florence, included other famous painting apprentices, such as Ghiarlandaio, Perugino, Botticelli, and Lorenzo di Credi. There, Leonardo followed a theoretical and technical training in drafting, chemistry, metallurgy, metal working, plaster casting, leather working, mechanics, carpentry, drawing, painting, sculpting and modelling,

training that was a solid foundation for his various future studies.

During his daily walk along the Arno river valley to reach the workshop, he observed the landscape carefully with all its elements (animal, plant, river etc) and increased his desire to understand the secrets of nature. We can say that Leonardo’s mission in life was to understand nature, trying to penetrate its secrets and deducing its laws.

For this reason he studied all the known science and art becoming: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist and writer. Because of his many interests he wrote a massive amount of manuscripts where he recorded all his projects, research, theories, curiosities, personal events and thoughts throughout his whole life. It is easy to undestand that all Leonardo’s works were considered very valuable


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while he was alive, so he tried to conceal the projects by dividing them into parts and spreading them among his notes. Also his peculiar writing method helped him in this.

He wrote in the boustrophedon way i.e. reverse side, probably caused by an optic disturbance so to understand the text you have to use a mirror.

After his death, all his manuscripts were stolen, sold, lost, appropriated or donated, so we now have only a fifth of Leonardo’s entire works.

These have now been organized in different codices. Many experts and engineers are studying and assembling the information. This booklet is a summary of their latest findings.

The village of Vinci, Italy


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The main problem that Leonardo had in his inventions was how to produce movement. Perhaps this was one of the reasons why he

did postmortem examinations. This caused him many troubles and he was obligated to leave Florence.

All his life Leonardo wrote an impressive profusion of notes and sketches, projects and drawings without any kind of organisation. Some projects were divided into parts and spread among different pages to hide the content from the viewer. As a result it was difficult to understand

the original ideas and to reconstruct the projects. Only following their collection into codices, were experts able to assemble the information. Madrid Codex I and II can be considered as the real mechanical manuals of that period.

In the codices there are hidden sketches of several self-propelling carts for use in the transportation of heavy items, not for people. In that period in fact, the main problem was how to move, transport and place in position large heavy objects, including columns, bells, cannons

and so on. The only resources available then were manpower and horse or other

animal power. Leonardo was called to solve these problems and designed several machines and winches.

In particular Leonardo tried to increase the energy by using a complicated system of gears and wheels.

THE SELF-PROPELLING

CART


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The result was that the

movement of the machine was very slow but the energy

generated was sufficient to solve the problem of

transport and placement. We do not have an example or proof of

the effective construction of these machines, probably because they were too big and expensive to built. Everything is deduced from the studies.

It was around 1478 when Leonardo planned the self propelling cart that was at the focus of scientific interest for many years. The sheet no.812 of the Codex Atlanticus shows this idea. Leonardo’s project was interpreted in several ways and this was the basis of the discussion during last past century.

(1) “In 1905, Gerolamo Calvi realized the importance of folio 812r of the Codex Atlanticus. In 1928 Guido Semenza identified the design for the so-called “self-

propelled cart” in the drawings on folios 812r of the Codex Atlanticus; he also recognized the

prototype of the modern differential, which allows two cart wheels to turn at different

speeds on bends in order to avoid dragging.”

Semenza pointed out that the design lacked the connection between the “Leaf springs” that provide the power and the two horizontal toothed wheels, i.e. the connection needed to convey movement to the cart wheels. Finally, he suggested that the two small pegged wheels at the corners were an escape mechanism for the drive system applied to the wheels and were intended to regulate the rate at which the springs unwind.


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In 1939, Arturo Uccelli was inspired by a 1938 publication in which Jotti da Badia Polesine suggested an alternative to Semenza’s interpretation of folio 812r. According to Jotti, the connection to the springs was made by way of ropes wound around the cylinders Leonardo had sketched in the centre of the two large toothed wheels.

Once the mechanism had been wound, releasing the springs would turn the cylinders and, therefore, the toothed wheels, thereby conveying movement to the cart wheels themselves. Uccelli had a new idea: he thought that there was a toothed

ring gear beneath the pegs of the small wheels, and that this engaged with the large toothed wheels,

which would explain the rotary mechanism of the two corner wheels.“ After several

attempts in 2004 experts were able to better understand

the project trying to discover the possible

solution of wheels, gears, steering and

springs. They built a self-propelling cart that worked perfectly and was able to cover several metres.

The studies are still continuing and, thanks to technology and computer graphics, theories are multiplying.

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THE MECHANICALLION

Leonardo was an observer of nature. In his work he described, drew and built machines inspired by nature. One of his wonderful machines was a mechanical lion.

When Leonardo was working as an architect for a wealthy Florentine merchant in Lyon, France in 1515, he was commissioned to build something astonishing to impress the French King, Francis I. The tribute had to be a welcome to the king, impressing him with the Italian genius.

The lion had to move towards the king and after few steps it had to open its chest where lots of lilies were situated, creating a floral cascade. There are no direct notes or sketches from Leonardo about this project but other artists (like Vasari) wrote about this event.

Michelangelo, for example wrote that the lion (1) “began to move, and rising in two movements, opened its chest, which was seen to be full of lilies.” This description was reported by Michelangelo but he was not a direct witness of the event.

This accounts for the extraordinary impact on public opinion. Experts think that the project was similar to the drawing “Study of

Leonardo’s drawing/ decorative soldier’s armour


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a mechanical horse” preserved in the

Windsor Castle Library. At the beginning of the study of this project, experts thought that the mechanism could imitate only the movement of the legs.

(1) “The legs operate like parts of a puppet: they can be raised, but they do not propel or provide any support for the structure. Like this, there would be a risk of the lion wobbling back and forward, but the tail could be used as a stabilizer.

Just as cats use their tails for balance, if the

mechanical tail rests on the ground it provides stability and the system

remains balanced. A mechanical lion able to stand on its own feet might also be

pulled by a cord, follow a track, or be pushed along by the tail: the weight and the movement of the wheels in the centre automatically simulate the animal’s gait.

However, experts can only guess as to the mechanisms that might make the lion move and stop on its own, or open its mouth or a trapdoor in its chest for flowers to come out. In codex Madrid I, Leonardo himself demonstrates how it is possible to make any kind of automated mechanical device.

Nonetheless, experts will try to use only da Vinci’s mechanics. The energy to make the robot self-

propelled could be provided by an internal spring connected to the main wheels by a tight card or by a simple gear. The spring/conical cylinder system comes from Madrid I.

The ideal place for the spring is in the middle of the pelvis so that both the weight and

Drawing of internal wheels


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the resulting centre of gravity will be held between the supports of the tail and the two central wheels. With this arrangement the lion stability was increased and it worked properly. At the end of its walk, the system providing the forward movement could release a hook that would cause the chest or jaws to open for the lilies to fall out by means of gravity.”

The space at the front it was large enough to hold a lot of flowers, or part of it could be used for other mechanisms.

This project can be clearly seen as a robot. It is amazing to think that the intention of Leonardo 500 years ago was to build a walking animal robot, because this is a real problem that our scientists are currently trying to perfect; the difficult aspect of movement.

As recently as 2000 a good example of a robotic quadruped was built, the Sony robot dog. Leonardo’s lion can be considered its historic forerunner.

Reconstruction from Leonardo’s studies“da Vinci’s Robots” by Mario Taddei


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THE ROBOT SOLDIER

There are many disputed theories about Leonardo’s knight. One of these is to see the project as a decorative clock, incorporating a

figure of a knight on the top. Others think that the knight was a mechanical choreographic puppet to use at the theatre.

But these theories have a inherant weakness, namely why divide and spread the project among pages of notes without a clear reference to these pages? It seems that Leonardo’s intention was to confuse the viewer rather than have some random notes about a new idea.

Because this was the first time Leonardo tried to hide information, studies suggest a different

interpretation and therefore they focus on a robot soldier. In 1482 Leonardo was working for Ludovico called Il Moro, Lord of Milan, as an architect, inventor, engineer, sculptor and painter. It was probably in this period that he thought about and planned the knight.

(1) “The detail that reminds us of a robot is folio no.579r-13. In this detail the pulleys, which are drawn with every possible shape and type of track, are arranged symmetrically so that they look like two arms and a head.

The pulleys can be placed inside the upper body armour to transmit

movement to the arms. How might the system work?

The problem is that only one cord connects all the pulleys, so the two robotic arms cannot

function independently. Furthermore, there is no

visible power source and the ends


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of the cord finish at the centre of the hands in a kind of closed mechanism.

If the central disc is turned alternately in the opposite direction, the effect is to make the mechanical soldier beat its hands on its chest, just like an angry gorilla. There are no known precedents, no one had ever thought of building a mechanical soldier operated by pulleys and mechanical devices.

During the studies of Leonardo’s robot, experts made a number of models to test their theories of how it might work. Finally, with regard to the robot soldier on folio 579, a small models proved that the idea was feasible and experts went on to design and build a full-scale model.

The dummy for the robot is made of wood. Walnut and elm are at the stress point, maple and oak are used for filler and limbs. The most complicated parts were the arms.

(1) They subjected the mechanical arms to numerous tests, especially fatigue. Armour is heavy and it is difficult to keep even human arms in a raised position because of the enormous stress it puts on the shoulders. To avoid the problem, two vertical lines might also represent the halberds held by the soldier, which would also act as a support for the arms.

Reconstruction from “da Vinci’s Robots“ by Mario Taddei


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In fact if the robot holds a halberd it not only makes him look more hostile, but also acts to buttress the enormous weight of the arms enabling it to work more efficiently. This functional detail only became evident during construction of the physical model after numerous artificial shoulders had broken.

The definitive model stands on its feet and is able to keep its arms raised. By turning the central disc, the arms move slowly to the right and left, conspicuously shaking the points of the halberds. All that remains is to make as many as required, put them on top of a tower and connect them to the central pulleys as Leonardo indicated.

Then, send the end of the cord to a system of rods linked to a mill and an army of mechanical soldiers will be ready to scare and frighten off anyone who intended to sack our castle.”

In conclusion, we have to say, as always, that anyone who wants to investigate Leonardo’s ideas will never run out of new things to discover. Leonardo designed countless mysterious and amazing devices hidden in his codices. In other words we can say that Leonardo’s amazing futuristic designs still hold some mystery yet to be unravelled by modern science. Such was the genius of the man.

Leonardo’s Museum Vinci Italy

REFERENCES

1. Mario Taddei (2007) “I Robot di Leonardo” L3 Leonardo edition.Printed by Petruzzi Citta’ di Castello (PG) Italy

2. Giunti editore www.Leonardonline.it Accessed 27/03/2010

3. www.wikipedia.co.uk “Leonardo da Vinci’s life“ Accessed 13/03/2010

4. The British Museum “Italian Renaissance drawings“ exibition guide April 2010


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The secrets of Leonardo

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