The Imperial and Royal Museum pursued different scopes: the promotion of Galilean and Newtonian physics by means of demonstrative machines, the creation of a vast collection of naturalistic specimens and the conducting of useful research in various fields of scientific knowledge. The research demanded the employment of specific apparatus. In the case of the observatory, Fontana sought to procure part of the necessary instruments abroad and, in particular, from London. Nevertheless, he was bound to trust the construction of the more complex and costly astronomical instruments to the already existing workshops of the Museum. To simplify the process of their construction “dividing machines” were expressly created, inspired by devices designed by the Duke of Chaulnes. Thanks to such machines, the process of dividing graduated scales until then carried out by means of rule and compass, was mechanised and remained notably more rapid and precise.
Circle Dividing Engine,
Florence; 1762; wood, brass, marble
To create a circular graduated scale, the circle to be divided was put on the rotating brass disc of the machine. The movements of the disc were regulated by a handle with an endless screw and verified by two microscopes. Other systems of screws delimited the run of the marking point.
Line Diving Engine,
Florence; end of the 18th C.; wood, brass, marble
This instrument was used to mark divisions on rectilinear graduated scales. A long screw placed at the extreme end of a wooden arm regulated with precision the distance of the marking point.