During the course of the year I chanced upon two exhibitions showing models of the machinery invented or developed by Leonardo da Vinci. One exhibition was in the Palazzo della Cancelleria in Rome, the other in Lugano Switzerland. There is also a permanent exhibition on the same theme at Amboise in France where Leonardo is buried, having spent the last two years of his life at the French court. Three generations of the Niccolai family of Florence have built 150 models and some of these are lent out for exhibitions and they also maintain a permanent exhibition in Florence.
Leonardo produced some 25,000 pages of notes and drawings during his lifetime of which only about 5,000 remain. On his death he left them to his disciple Francesco Melzi who looked after them but subsequently they were broken up and dispersed. They are now divided into as many as 10 codices, one of them being housed in the Royal collection at Windsor Castle.
One of his most innovative contributions to technology was his analysis of the components of machines, carried out from the 1490’s onwards. He was not only familiar with simple mechanisms such as the winch, lever and pulley but he developed them is such a way as to apply them to complex machines which allowed operations to be carried out automatically.
He made an accurate classification of screws and the ways in which they could be used. He studied cogwheels and their combinations. He developed the use of blocks and pulleys for lifting heavy loads. He realised that lubrication was not sufficient to prevent the wear of machine parts so he developed various of ball bearings which prefigure those we use today. He also suggested the use of pistons for converting rotary motion into reciprocating motion and was aware of the function of flywheels for regulating movement of rotating axles.
Although Leonardo regarded war as a ‘most bestial madness’ nevertheless he was involved in analysing arms and war machines. As an engineer in the services of Ludovico il Moro, Duke of Milan, He had to design both firearms and more traditional siege machines and catapults. The invention of gunpowder in the 14th century did not immediately intail the disappearance of earlier weapons. Swords and firearms were used together for a long time. There was a constant striving not so much to design new weapons but to improve the efficiency of existing ones. He devised ways of making more rudimentary cannons and bombards more efficient. He also examined the form and trajectory of projectiles to increase firing accuracy. From his experiments with jets of water he produced a parabolic curve that anticipated Galileo and Newton’s studies of parabolas and the principle of inertia.
Leonardo’s interest in water probably began when he was a pupil of Verocchio in Florence and had some experience with fountains. However, it was when he moved to Lombardy in the service of the Duke of Milan that he had to apply himself to the fundamental problem of water as he was having to deal with canals, irrigation and the working of mill machinery.
He carefully observed the flow of rivers and currents and the flow of water through glass models. He then applied these observations to the practical problems of canal building and locks. He even produced a scheme for diverting the River Arno and connecting Florence to the sea with a navigable canal. Fascinated by the idea of enabling men to move on and under water, he designed buoys, breathing equipment, faster boats with improved hull design and pontoon bridges. The need to drain basins and marshland involved Leonardo in improving machines and pumps which had been known from ancient times such as the Archimedean screw and water wheels.
Again, his early interest in flight devoloped after he moved to Milan in about 1482. After observing birds, he believed that flight was du to the beating of the wing on air. For that reason he concentrated his research on the design of the wing in its form and structure.
Most of his flying machines are equipped with wings, usually beating. However, one of his most fundamental insights was the fact that air is compressible and therefore exerts a resistance capable of supporting a weight. One of the first applications of this observation was his design and construction of a rigid parachute with a base and height of 7.2 metres, covered with starched linen to make it impermeable and airtight. About the same time there was another application of the principle of air resistance, the so-called ‘air screw’, which can be seen as the prototype of the helicopter. In addition to these studies of flight he also investigated associated problems such as instruments for navigation and meteorological instruments.
With such a staggering array of study and invention, one can only wonder just what has been lost with the missing 80% of his notebooks.