I AM very much obliged to Prof. Everett and Mr. J. J. Walker for having taken the trouble to point out that the theorem which I communicated to NATURE is, so far as it relates to uniplanar motion, already known. I am indebted to Prof. Uuwin for more complete information on the subject. He tells me that the theorem (for the uniplanar case) has been employed by German engineers in the discussion of stresses produced in moving pieces—exactly the use of the theorem which naturally presents itself. Moreover, the theorem (for the uniplanar case) will be found in § 198 of Collignon's “Cinématique,” as well as in other foreign books, but not, so far as my information goes, in the work of any English author. None of your correspondents or of mine are however able to say that the general case was previously known.

Affiliations

1. Royal Engineering College, Cooper's Hill, December 13

   • GEORGE M. MINCHIN

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Publication history

DOI

https://doi.org/10.1038/023170c0

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