The mysterious double cone

The mysteriously upward rolling double cone is a classic teaching example from the lessons in mechanics, where a supposed paradox is used to be able to discuss the characteristics of the center of gravity motion of a body. The structure consists of a base, whose running frame has a slope toward the center opposite the ends, and a double cone that, when placed on the base, runs toward the center of the frame.

The specimen in our HistoLab is based on an exhibit from the Dutch museum in Leiden, which was made by the company HistEx GmbH in Oldenburg. The physical cabinet in Leiden attributes it to the collection of 'sGravesande, but it definitely does not correspond to the design of 'sGravesande, who had envisaged a completely different configuration with a centrally mounted flywheel in his treatise. Provenance research in Leiden indicates that the double cone located there probably originated in the collection of Paets of Troostwijk and was taken over into the Leiden collection in 1790. As a possible precursor, reference is made there to an engraving from Whiston's Treatise on Mechanics.


W.J. 's Gravesande, Physices Elementa Mathematica (Leiden 17423), par. 210 en Tab. VII, fig. 2
Peter de Clercq, The Leiden Cabinet of Physics, a descriptive Catalogue (1997), p. 22
Hauksbee, Francis, Jr., and William Whiston. 1714. A Course of Mechanical, Optical, Hydrostatical, and Pneumatical Experiments.