Credit: ©The Royal Society
    Image number: RS.15013

    Glass instrument for Torricellian experiment

    Date
    September-October 1672
    Creator
    Unknown, Artist
    Object type
    Archive reference number
    LBC
    Manuscript page number
    vol5 p419
    Material
    Dimensions
    height (page): 301mm
    width (page): 176mm
    Subject
    Physics
       > Vacuum physics
          > Pneumatics
    Content object
    Description
    A line drawing indicating a glass tube in a tub of mercury for a Torricellian experiment. 'a' at the top indicates a very small hole, to be immersed in water. William Brouncker suggested to John Wallis that this instrument would demonstrate that there were smaller and heavier particles of air that could penetrate the glass, which Brouncker suggested as an explanation of the suspension of mercury in the Torricellian experiment at a higher level than its usual height of 29 inches. Discussion of this topic took place at the meeting of the Royal Society on 30 October 1672, occasioned by Christian Huygens's report on this phenomenon in Philosophical Transactions of the Royal Society, vol. 7, no. 86.

    This image was copied from LBO/5/381.
    Transcription
    I desire Dr Wallis may know, that in my Opinion in this Case his Objections doe totally vanish, especially if (as I intend to try) a large cane of Glass may be made to stand topp full of Mercury below the Standard of 29 inches, with a little hole on the Top thereof, as at a, immerged (sic) in water if Air be too subtile for our mechanicks.
    Transcribed by the Making Visible project
    Related fellows
    William Brouncker, 2nd Viscount Brouncker of Lyons (1620 - 1684, British) , Mathematician
    John Wallis (1650, British) , Mathematician
    Christiaan Huygens (1629 - 2006, Dutch) , Natural philosopher
    Associated place
    <The World>
       > Europe
          > United Kingdom
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