Study for a painting of Isabella d'Este
Fascinated by the phenomenon of flight, Leonardo produced detailed studies of the flight of birds, and plans for several flying machines, including a helicopter powered by four men (which would not have worked since the body of the craft would have rotated) and a light hang-glider which could have flown. On January 3, 1496 he unsuccessfully tested a flying machine he had constructed. PBS aired a special about the building and testing of a glider based on Da Vinci's design. The glider was a resounding success, flying farther and longer than the Wright Brothers' plane.
In 1502 Leonardo da Vinci produced a drawing of a single span 720-foot (240 m) bridge as part of a civil engineering project for Sultan Beyazid II of Constantinople. The bridge was intended to span an inlet at the mouth of the Bosphorus known as the Golden Horn. It was never built, but Leonardo's vision was resurrected in 2001 when a smaller bridge based on his design was constructed in Norway.
Owing to his employment as a military engineer, his notebooks also contain several designs for military machines: machine guns, an armoured tank powered by humans or horses, cluster bombs, etc. even though he later held war to be the worst of human activities. Other inventions include a submarine, a cog-wheeled device that has been interpreted as the first mechanical calculator, and a car powered by a spring mechanism. In his years in the Vatican, he planned an industrial use of solar power, by employing concave mirrors to heat water. While most of Leonardo's inventions were not built during his lifetime, models of many of them have been constructed with the support of IBM and are on display at the Leonardo da Vinci Museum at the Château du Clos Lucé in Amboise
Science
Perhaps even more impressive than his artistic work are his studies in science and engineering, recorded in notebooks comprising some 13,000 pages of notes and drawings, which fuse art and science. These notes were made and maintained through Leonardo's travels through Europe, during which he made continual observations of the world around him. He was left-handed and used mirror writing throughout his life. This is explainable by the fact that it is easier to pull a quill pen than to push it; by using mirror-writing, the left-handed writer is able to pull the pen from right to left.
His approach to science was an observatory one: he tried to understand a phenomenon by describing and depicting it in utmost detail, and did not emphasize experiments or theoretical explanations. Throughout his life, he planned a grand encyclopedia based on detailed drawings of everything. Since he lacked formal education in Latin and mathematics, contemporary scholars mostly ignored Leonardo the scientist.
As did most people at the time, he believed that the Sun revolved around the Earth, and that the Moon reflects the sun's light due to its being covered by water.
Anatomy
Leonardo started to discover the anatomy of the human body at the time he was apprenticed to Andrea del Verrocchio, as his teacher insisted that all his pupils learn anatomy. As he became successful as an artist, he was given permission to dissect human corpses at the hospital Santa Maria Nuova in Florence. Later he dissected also in Milano in the hospital Maggiore and in Rome in the hospital Santo Spirito (the first mainland Italian hospital).
From 1510 to 1511 he collaborated with the doctor Marcantonio della Torre (1481 to 1511). 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 1580 (long after his death) under the heading Treatise on painting.
A page from Leonardo's journal showing his study of a foetus in the womb.
Leonardo drew many images of the human skeleton, and 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 vertebrae. He was also able to represent exceptionally well the human skull and cross-sections of the brain (transversal, sagittal, and frontal). He drew many images of the lungs, mesentery, urinary tract, sex organs, and even coitus. He was one of the first who drew the fetus in the intrauterine position (he wished to learn about "the miracle of pregnancy").
He often drew muscles and tendons of the cervical muscles and of the shoulder. He was a master of topographic anatomy. He not only studied the anatomy of human, but also of other beings. It is important to note that he was not only interested in structure but also in function, so he was anatomist and physiologist at the same time. Because he actively searched for bodily deformed people to paint them, he is also considered to be the beginner of caricature.
His study of human anatomy led also to the design of the first known robot in recorded history. The design, which has come to be called Leonardo's robot, was probably made around the year 1495 but was rediscovered only in the 1950s. It is not known if an attempt was made to build the device. A diagram drawing Leonardo did of a heart inspired a British heart surgeon to pioneer a new way to repair damaged hearts in 2005.
His notebooks
Anatomical study of the arm.
Leonardo's notebooks were on four main themes; architecture, elements of mechanics, painting and human anatomy. These 'notebooks' - originally loose papers of different types and sizes, distributed by friends after his death - have found their way into major collections such as the Louvre, the Biblioteca Nacional de España, the Biblioteca Ambrosiana in Milan, and the British Library. The British Library has put a selection from its notebook (BL Arundel MS 263) on the web in its Turning the Pages section.
The Codex Leicester is the only major scientific work of Leonardo's in private hands. It is owned by Bill Gates, and is displayed once a year in different cities around the world. Why Leonardo did not publish or otherwise distribute the contents of his notebooks remains a mystery to those who believe that Leonardo wanted to make his observations public knowledge. Technological historian Lewis Mumford suggests that Leonardo kept notebooks as a private journal, intentionally censoring his work from those who might irresponsibly use it (the tank, for instance).
They remained obscure until the 19th century, and were not directly of value to the development of science and technology. In January 2005, researchers discovered the hidden laboratory used by Leonardo da Vinci for studies of flight and other pioneering scientific work in previously sealed rooms at a monastery next to the Basilica of the Santissima Annunziata, in the heart of Florence