LEONARDO - THE IDEAL CITY

This is one of the very few drawings in which Leonardo used the exploded-view technique to illustrate the individual parts of the machine, which is also shown fully assembled. The representation of the individual parts may be due to the fact that Leonardo designed them from an existing device or machine, which he altered and improved, with special attention to the breaking system and to the construction technique of the teeth of the two wheels (detail in the bottom right-hand corner).
The drawing may be dated between 1478 and 1480 and recalls the technological achievements of the Florentine engineers and, in particular, the machines designed by Filippo Brunelleschi for the construction of the dome of Santa Maria del Fiore in Florence. Of particular interest is the manufacturing system of the teeth for the gearwheels, as illustrated in the bottom right-hand corner of the drawing. In order to solve the difficulties involved in manufacturing them from a solid wooden wheel, Leonardo suggests using wooden blocks held in a slanted position by means of wooden stakes, which would fix them to the inner part of the rim of their respective wheels. Besides fixing the wooden blocks, the stakes would mesh with the spider of the shaft and make it rotate. On the upper part of the folio there is an illustration of a hygrometer and, under it, there is a component of a modular ladder.