Leonardo da Vinci (1452–1519) was an Italian polymath, regarded as the epitome of the "Renaissance Man", displaying skills in numerous diverse areas of study. While most famous for his paintings such as the Mona Lisa and the Last Supper, Leonardo is also renowned in the fields of civil engineering, chemistry, geology, geometry, hydrodynamics, mathematics, mechanical engineering, optics, physics, pyrotechnics, and zoology.

While the entire extent of his scientific studies has only become recognized in the last 150 years, during his lifetime he was employed for his engineering and skill of invention. Many of his designs, such as the movable dikes to protect Venice from invasion, proved too costly or impractical. Some of his less significant inventions entered the world of manufacturing unheralded. As an engineer, Leonardo conceived ideas vastly ahead of his own time, conceptually inventing the parachute, the helicopter, an armored fighting vehicle, the use of concentrated solar power, the car and a gun, a rudimentary theory of plate tectonics and the double hull. In practice, he greatly advanced the state of knowledge in the fields of anatomy, astronomy, civil engineering, optics, and the study of water (hydrodynamics).

One of Leonardo's drawings, the Vitruvian Man, is a study of the proportions of the human body, linking art and science in a single work that has come to represent the concept of macrocosm and microcosm in Renaissance humanism.

Approach to scientific investigation

During the Renaissance, the study of art and science was not perceived as mutually exclusive; on the contrary, the one was seen as informing upon the other. Although Leonardo's training was primarily as an artist, it was largely through his scientific approach to the art of painting, and his development of a style that coupled his scientific knowledge with his unique ability to render what he saw that created the outstanding masterpieces of art for which he is famous.

As a scientist, Leonardo had no formal education in Latin and mathematics and did not attend a university. Because of these factors, his scientific studies were largely ignored by other scholars. Leonardo's approach to science was one of intense observation and detailed recording, his tools of investigation being almost exclusively his eyes. His journals give insight into his investigative processes.

As a researcher, Leonardo divided nature and phenomena into ever smaller segments, concretely with knives and measuring instruments, intellectually with formulas and numbers, to wrest the secrets of creation from it. The smaller the particles, runs the assumption; the closer one will get to the solution of the enigmas.

A recent and exhaustive analysis of Leonardo as a scientist by Fritjof Capra argues that Leonardo was a fundamentally different kind of scientist from Galileo, Newton, and other scientists who followed him, his theorizing and hypothesizing integrating the arts and particularly painting. Capra sees Leonardo's unique integrated, holistic views of science as making him a forerunner of modern systems theory and complexity schools of thought.Capra, Fritjof. The Science of Leonardo; Inside the Mind of the Genius of the Renaissance. (New York, Doubleday, 2007)

Notes and journals

Leonardo kept a series of journals in which he wrote almost daily, as well as separate notes and sheets of observations, comments and plans. He wrote and drew with his left hand, and most of his writing is in mirror script, which makes it difficult to read. Much has survived to illustrate Leonardo's studies, discoveries and inventions.

On his death, the writings were left mainly to his pupil and heir Francesco Melzi, with the apparent intention that his scientific work should be published. Sometime before 1542, Melzi gathered together the papers for A Treatise on Painting from eighteen of Leonardo's 'books' (two-thirds of which have gone missing). The publishing did not take place in Melzi's lifetime, and the writings were eventually bound in different forms and dispersed. Some of Leonardo's works were published as A Treatise on Painting over a century after his death.

Publication

Leonardo illustrated a book on mathematical proportion in art written by his friend Luca Pacioli and called De divina proportione, published in 1509. He was also preparing a major treatise on his scientific observations and mechanical inventions. It was to be divided into a number of sections or "Books", Leonardo leaving some instructions as to how they were to be ordered. Many sections of it appear in his notebooks.

These pages deal with scientific subjects generally but also specifically as they touch upon the creation of artworks. In relating to art, this is not science that is dependent upon experimentation or the testing of theories. It deals with detailed observation, particularly the observation of the natural world, and includes a great deal about the visual effects of light on different natural substances such as foliage.Jean Paul Richter editor 1880, The Notebooks of Leonardo da Vinci Dover, 1970, . (accessed 2007-02-04)

Leonardo wrote:

Begun at Florence, in the house of Piero di Braccio Martelli, on the 22nd day of March 1508. And this is to be a collection without order, taken from many papers which I have copied here, hoping to arrange them later each in its place, according to the subjects of which they may treat. But I believe that before I am at the end of this [task] I shall have to repeat the same things several times; for which, O reader! do not blame me, for the subjects are many and memory cannot retain them [all] and say: 'I will not write this because I wrote it before.' And if I wished to avoid falling into this fault, it would be necessary in every case when I wanted to copy [a passage] that, not to repeat myself, I should read over all that had gone before; and all the more since the intervals are long between one time of writing and the next.

Natural science

Light Leonardo wrote:

The lights which may illuminate other bodies that's of 4 kinds. These are; diffused light as that of the atmosphere; And Direct, as that of the sun; The third is Reflected light; and there is a 4th which is that which passes through [translucent] bodies, as linen or paper etc.

For an artist working in the 15th century, some study of the nature of light was essential. It was by the effective painting of light falling on a surface that modelling, or a three-dimensional appearance was to be achieved in a two-dimensional medium. It was also well understood by artists like Leonardo's teacher, Verrocchio, that an appearance of space and distance could be achieved in a background landscape by painting in tones that were less in contrast and colours that were less bright than in the foreground of the painting. The effects of light on solids were achieved by trial and error, since few artists except Piero della Francesca actually had accurate scientific knowledge of the subject.

At the time when Leonardo commenced painting, it was unusual for figures to be painted with extreme contrast of light and shade. Faces, in particular, were shadowed in a manner that was bland and maintained all the features and contours clearly visible. Leonardo broke with this. In the painting generally titled The Lady with an Ermine (about 1483) he sets the figure diagonally to the picture space and turns her head so that her face is almost parallel to her nearer shoulder. The back of her head and the further shoulder are deeply shadowed. Around the ovoid solid of her head and across her breast and hand the light is diffused in such a way that the distance and position of the light in relation to the figure can be calculated.

Leonardo's treatment of light in paintings such as The Virgin of the Rocks and the Mona Lisa had a serious impact on the way in which artists perceived light and used it in their paintings. Of all Leonardo's scientific legacies, this is probably the one that had the most immediate and noticeable effect.

Human anatomy Leonardo wrote: ...to obtain a true and perfect knowledge ... I have dissected more than ten human bodies, destroying all the other members, and removing the very minutest particles of the flesh by which these veins are surrounded, ... and as one single body would not last so long, since it was necessary to proceed with several bodies by degrees, until I came to an end and had a complete knowledge; this I repeated twice, to learn the differences...

Topographic anatomy Leonardo began the formal study of the topographical anatomy of the human body when apprenticed to Andrea del Verrocchio. As a student he would have been taught to draw the human body from life, to memorize the muscles, tendons and visible subcutaneous structure and to familiarise himself with the mechanics of the various parts of the skeletal and muscular structure. It was common workshop practice to have plaster casts of parts of the human anatomy available for students to study and draw.

If, as is thought to be the case, Leonardo painted the torso and arms of Christ in The Baptism of Christ on which he famously collaborated with his master Verrocchio, then his understanding of topographical anatomy had surpassed that of his master at an early age as can be seen by a comparison of the arms of Christ with those of John the Baptist in the same painting.

In the 1490s he wrote about demonstrating muscles and sinews to students:

Remember that to be certain of the point of origin of any muscle, you must pull the sinew from which the muscle springs in such a way as to see that muscle move, and where it is attached to the ligaments of the bones.

His continued investigations in this field occupied many pages of notes, each dealing systematically with a particular aspect of anatomy. It appears that the notes were intended for publication, a task entrusted on his death to his pupil Melzi.

In conjunction with studies of aspects of the body are drawings of faces displaying different emotions and many drawings of people suffering facial deformity, either congenital or through illness. Some of these drawings, generally referred to as "caricatures", on analysis of the skeletal proportions, appear to be based on anatomical studies.

Dissection

As Leonardo became successful as an artist, he was given permission to dissect human corpses at the Hospital of Santa Maria Nuova in Florence. Later he dissected in Milan at the hospital Maggiore, and in Rome at the Ospedale di Santo Spirito (the first mainland Italian hospital). From 1510 to 1511 he collaborated in his studies with the doctor Marcantonio della Torre.

I have removed the skin from a man who was so shrunk by illness that the muscles were worn down and remained in a state like thin membrane, in such a way that the sinews instead of merging in muscles ended in wide membrane; and where the bones were covered by the skin they had very little over their natural size.

In 30 years, Leonardo dissected 30 male and female corpses of different ages. Together with Marcantonio, he prepared to publish a theoretical work on anatomy and made more than 200 drawings. However, his book was published only in 1680 (161 years after his death) under the heading A Treatise on Painting.

Among the detailed images that Leonardo drew are many studies of the human skeleton. He was the first to describe the double S form of the backbone. He also studied the inclination of pelvis and sacrum and stressed that sacrum was not uniform, but composed of five fused vertebrae. He also studied the anatomy of the human foot and its connection to the leg, and from these studies, he was able to further his studies in biomechanics.