Credit: ©The Royal Society
    Image number: RS.14746

    A pocket-sized level

    Date
    27 March 1686
    Object type
    Archive reference number
    Manuscript page number
    p336
    Material
    Dimensions
    height (page): 320mm
    width (page): 195mm
    Subject
    Content object
    Description
    A figure of a pocket-sized level designed by Robert Hooke, in a letter by Thomas Gale to St George Ashe dated 27 March 1686. Although this figure differs considerably from the one found among the papers of the Dublin Philosophical Society (Add. Ms. 4811, 117v, British Library), the principles illustrated here are the same.

    This figure is copied from EL/H3/42/001.
    Transcription
    '...a new Level, whereby he pretends by a very small Instrument, and which may be made almost to be carried in your Pocket to discover the Horizontal Line for all Uses to the utmost Rigour of Exactness.

    AB, CD are two Rulers at right Angles, the one to the other. EF is a third erected at right Angles on the Intersection of the other two, but cut away at the bottom, that so the Wire FG may be fasten'd to the Center of the Instrument in F, to give the Axis EF a small Inclination towards C.
    Transcribed by the Making Visible project
    Related fellows
    Thomas Gale (1635 - 1702, British) , Antiquary
    St George Ashe (1658 - 1718, British) , Mathematician
    Robert Hooke (1635 - 1703, British) , Natural philosopher
    Associated place
    <The World>
       > Europe
          > United Kingdom
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