)
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. which, by Medieval tradition, was located at the exact physical center of the skull. Leonardo studied internal organs, being the first to draw the human
appendix and the
lungs,
mesentery,
urinary tract,
reproductive organs, the muscles of the
cervix and a detailed cross-section of
coitus. He was one of the first to draw a scientific representation of the
fetus in the intrautero. Leonardo studied the
vascular system and drew a dissected
heart in detail. He correctly worked out how heart valves ebb the flow of blood yet he did not fully understand
circulation, as he believed that blood was pumped to the muscles where it was consumed. In 2005 a UK heart surgeon, Francis Wells, from Papworth Hospital Cambridge, pioneered repair to damaged hearts, using Leonardo's depiction of the opening phase of the mitral valve to operate without changing its diameter allowing an individual to recover more quickly. Wells said "Leonardo had a depth of appreciation of the anatomy and physiology of the body – its structure and function – that perhaps has been overlooked by some." Leonardo's observational acumen, drawing skill, and the clarity of depiction of bone structures reveal him at his finest as an anatomist. However, his depiction of the internal soft tissues of the body are incorrect in many ways, showing that he maintained concepts of anatomy and functioning that were in some cases millennia old, and that his investigations were probably hampered by the lack of preservation techniques available at the time. Leonardo's detailed drawing of the internal organs of a woman reveal many traditional misconceptions. Leonardo's study of
human anatomy led also to the design of an
automaton which has come to be called
Leonardo's robot, was probably made around the year 1495 but was rediscovered only in the 1950s.
Comparative anatomy Leonardo not only studied human anatomy, but the anatomy of many other animals as well. He dissected
cows,
birds,
monkeys and
frogs, comparing in his drawings their anatomical structure with that of humans. On one page of his journal Leonardo drew five profile studies of a horse with its teeth bared in anger and, for comparison, a snarling lion and a snarling man. I have found that in the composition of the human body as compared with the bodies of animals, the organs of sense are duller and coarser... I have seen in the Lion tribe that the sense of smell is connected with part of the substance of the brain which comes down the nostrils, which form a spacious receptacle for the sense of smell, which enters by a great number of cartilaginous vesicles with several passages leading up to where the brain, as before said, comes down. Leonardo's study of plants, resulting in many detailed drawings in his notebooks, was not to record in diagrammatic form the parts of the plant, but rather, as an artist and observer to record the precise appearance of plants, the manner of growth and the way that individual plants and flowers of a single variety differed from one another. One such study shows a page with several species of flower of which ten drawings are of wild violets. Along with a drawing of the growing plant and a detail of a leaf, Leonardo has repeatedly drawn single flowers from different angles, with their heads set differently on the stem. Apart from flowers the notebooks contain many drawings of crop plants including several types of grain and a variety of berries including a detailed study of
bramble. There are also water plants such as
irises and
sedge. His notebooks also direct the artist to observe how light reflects from foliage at different distances and under different
atmospheric conditions. A number of the drawings have their equivalents in Leonardo's paintings. An elegant study of a stem of
lilies may have been for one of Leonardo's early Annunciation paintings, carried in the hand of the Archangel Gabriel. In both the Annunciation pictures the grass is dotted with blossoming plants. The plants which appear in the Louvre version of
The Virgin of the Rocks reflects the results of Leonardo's studies in a meticulous realism that makes each plant readily identifiable to the botanist. In
A Treatise on Painting, Leonardo proposed the following
branching rule: All the branches of a tree at every stage of its height when put together are equal in thickness to the trunk [below them].
Cartography In the early 16th century
maps were rare and often inaccurate. Leonardo produced several extremely accurate maps such as the town plan of
Imola created in 1502 in order to win the
patronage of
Cesare Borgia. Borgia was so impressed that he hired him as a
military engineer and
architect. Leonardo also produced a map of
Chiana Valley in
Tuscany, which he surveyed, without the benefit of modern equipment, by pacing the distances. In 1515, Leonardo produced a map of the Roman Southern Coast which is linked to his work for the
Vatican and relates to his plans to drain the marshland. Recent research by Donato Pezzutto suggests that the background landscapes in Leonardo's paintings depict specific locations as aerial views with enhanced depth, employing a technique called
cartographic perspective. Pezzutto identifies the location of the
Mona Lisa to the Val di Chiana, the
Annunciation to the Arno Valley, the
Madonna of the Yarnwinder to the Adda Valley and
The Virgin and Child with St Anne to the Sessia Valley.
Hydrodynamics Leonardo wrote: All the branches of a water [course] at every stage of its course, if they are of equal rapidity, are equal to the body of the main stream.
Astronomy Leonardo lived at a time when
geocentric theories were the most widely used explanations to account for the relationship between the Earth and Sun's movement. He wrote that "The Sun has substance, shape, movement, radiance, heat, and generative power; and these qualities all emanate from itself without its diminution." He further wrote, The earth is not in the centre of the Sun's orbit nor at the centre of the universe, but in the centre of its companion elements, and united with them. And any one standing on the moon, when it and the sun are both beneath us, would see this our earth and the element of water upon it just as we see the moon, and the earth would light it as it lights us. In one of his notebooks, there is a note in the margin which states, "The Sun does not move," which may indicate Leonardo's support of
heliocentrism.
Alchemy Claims are sometimes made that Leonardo da Vinci was an
alchemist. He was trained in the workshop of Verrocchio, who according to Vasari, was an able alchemist. Leonardo was a chemist insofar as he experimented with different media for suspending
paint pigment. In the painting of murals his experiments resulted in notorious failures, with
The Last Supper deteriorating within a century, and
The Battle of Anghiari running off the wall. In Leonardo's many pages of notes about artistic processes, there are some that pertain to the use of silver and gold in artworks, information he would have learned as a student. Leonardo's scientific process was based mainly upon observation. His practical experiments are also founded in observation rather than belief. Leonardo, who questioned the order of the
Solar System and the deposit of fossils by the
Great Flood, had little time for the alchemical quests to turn
lead into
gold or create a
potion that gave eternal life. Leonardo said about alchemists: The false interpreters of nature declare that quicksilver is the common seed of every metal, not remembering that nature varies the seed according to the variety of the things she desires to produce in the world. Old alchemists... have never either by chance or by experiment succeeded in creating the smallest element that can be created by nature; however [they] deserve unmeasured praise for the usefulness of things invented for the use of men, and would deserve it even more if they had not been the inventors of noxious things like poisons and other similar things which destroy life or mind. And many have made a trade of delusions and false miracles, deceiving the stupid multitude. ==Mathematical studies==