Peano pp 56-63 | Cite as

The Controversy with Volterra

  • Hubert C. Kennedy
Part of the Studies in the History of Modern Science book series (SHMS, volume 4)


On 29 October, 1894, Etienne Jules Marey, a distinguished physiologist and pioneer in motion photography, presented to the Academy of Sciences of Paris a sequence of 32 photographs he had made of the fall of a cat dropped with feet upward. They showed that the cat completed exactly a half turn. This seemed to be in contradiction to the principle in mechanics of the conservation of angular momentum, and gave rise to a discussion in which several members of the Academy and, later, even the daily newspapers took part, several explanations being given of how the cat was able to turn over. In the January 1895 issue of the Rivista di Matematica, Peano gave another explanation in ‘The principle of the conservation of angular momentum and the story of a cat’ [77]. After mentioning several other possible explanations, he wrote:

But the explanation of the cat’s motion appears to me quite simple. When the animal is left to itself, it describes with its tail a circle in the plane perpendicular to the axis of its body. Consequently, by the principle of the conservation of angular momentum, the rest of its body must rotate in the sense opposite to the tail. When it has rotated as much as it wishes, it halts its tail and with this simultaneously stops its rotary motion, saving in this way itself and the principle of angular momentum.


Angular Momentum Gulf Stream Rotary Motion Royal Academy Daily Newspaper 
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Copyright information

© Martinus Nijhoff Publishers bv, The Hague 1980

Authors and Affiliations

  • Hubert C. Kennedy
    • 1
  1. 1.Department of MathematicsProvidence CollegeProvidenceUSA

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