Between Mechanics and Harmony: The Drawing of Lissajous Curves.

The contribution describes some aspects related to the representation of special curves; recalling mechanisms created specifically for the design of these curves, which have particular characteristics. Through the construction of a simple apparatus, consisting of two pendulums—which oscillate at the same time- it is possible to graphically reproduce Lissajous' experiments on the commuting vibrations of the diapasons. This equipment was first built by Samuel Charles Tisley (London 1829-Unknown), under the name of harmonographer. The contribution aslo illustrates the essential characteristics of the harmonograph—born as a means of analysing vibrations—but which, by its principle belongs to mechanics, for its applications to acoustic science and geometry for the ability to draw "harmonious" curves. [ABSTRACT FROM AUTHOR]