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.

该贡献描述了与特殊曲线表示相关的一些方面；回顾专门为这些曲线设计而创建的机制，这些曲线具有特定的特征。通过构造一个由两个同时振荡的摆组成的简单装置，可以图形化地再现利萨如关于音叉交换振动的实验。该设备最初由塞缪尔·查尔斯·蒂斯利（Samuel Charles Tisley，伦敦，1829 年 - 未知）以和声师的名义制造。该贡献还说明了谐波仪的基本特征——作为分析振动的一种手段而诞生——但从原理上讲，它属于力学，因为它应用于声学科学和几何学，能够绘制“和谐”曲线。