Credit: ©The Royal Society
    Image number: RS.15985

    Diagrams of cycloids

    Date
    15 July 1673
    Creator
    John Wallis (1616 - 1703, British) , Mathematician
    Object type
    Archive reference number
    Manuscript page number
    p1
    Material
    Dimensions
    height (page): 312mm
    width (page): 202mm
    Subject
    Description
    Diagrams of 'imperfect' cycloids by John Wallis. In response to Francis Jessop's comments on his theory of tides, Wallis explained that the imperfect cycloid did not have its base ba as the perpendicular to the curve ac (as Jessop supposed and as shown in the top diagram), but that the base ba was a tangent to the curve ac and perpendicular to it at ap (as in the bottom figure). Wallis originally made his comments in the margin of Jessop's letter dated 25 June 1673 and addressed to Martin Lister, who had forwarded it to Henry Oldenburg so that Wallis could comment on it.

    Copies can be found at LBO/6/190 and LBC/6/219. For Jessop's diagrams, see EL/I1/165/001.

    Francis Jessop (1638-91) was a freeman of the Cutler's Company of Sheffield, and a close friend of John Ray (Correspondence of Henry Oldenburg, ed. by Hall and Hall, vol. 10, p. 71n).
    Related fellows
    John Wallis (1616 - 1703, British) , Mathematician
    Henry Oldenburg (1612 - 1677, German) , Scientific correspondent
    Associated place
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