Between uncertainty and fraud

In the 18th century, views on the feasibility of perpetual motion remained confused. Within the context of the physics developed by Isaac Newton, however, the conviction emerged that—in the real world—the value of a dynamic effect could never be exactly equal to or even greater than its own cause. In other words, a part, however small, of the momentum of a mechanical system is always lost in resistance and attrition. This belief did not stop theorists, who conjectured the possible existence of natural forces of a different type from the three then known: gravitation, electrical force, and magnetic force. Nor did it deter inventors, ever in search of that “tiny something” capable of making their mechanical dreams come true. Most of all, it did not dissuade fraudsters, who, amid the general uncertainty, often established their credibility and obtained subsidies.

Mechanism for a bell tower clock with verge escapement and foliot
Northern Italy , late 15th century
Florence, Museo Galileo, inv. 3934, Del Vecchio donation
Giuseppe Campani (attr.), Perpetual motion clock
Giuseppe Campani (attr.)
Rome , 1660-1680
Florence, Museo Galileo, inv. 713
Jacob Leupold, Theatrum Machinarum Generale - Perpetual overbalanced wheel with spheres
Jacob Leupold
Theatrum Machinarum Generale
Leipzig, druckts Christoph Zunkel, 1724, p. 29
Mechanical paradox
Italian make
Early 19th century
Florence, Museo Galileo, inv. 1343
Zamboni’s “Perpetual electromotor” and its parts
Italian make
Second half of the 19th century
Florence, Museo Galileo, inv. 390 and H439
Giuseppe Zamboni, Descrizione ed uso dell’elettromotore perpetuo
Giuseppe Zamboni
Verona, Tipografia Mainardi, 1814
Florence, Museo Galileo Library, Misc. Med 023
George Linton, New method of impelling machinery without the aid of steam, water, wind, air, or fire
George Linton
The European Magazine, 81, February-June 1822, p. 188