Credit: ©The Royal Society
    Image number: RS.14813

    Glass instrument for a Torricellian experiment

    Date
    September-October 1672
    Object type
    Archive reference number
    Manuscript page number
    p381
    Material
    Dimensions
    height (page): 313mm
    width (page): 197mm
    Subject
    Physics
       > Vacuum physics
          > Pneumatics
    Content object
    Description
    A line drawing in the margin 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 of London vol. 7, no. 86 (1672).

    This image was copied into LBC/5/419.
    Object history
    At the meeting of the Royal Society on 30 October 1672, ‘Since during the Society’s recess there had been communicated to the members, who then met at Gresham-college, Mons. Huygens’s conjecture about the odd phaenomenon of the mercury’s standing top-full of well cleansed air, even to the height of seventy-five inches; and since the president and Dr. Wallis had suggested divers experiments determining the cause of that effect; it was inquired what had been done in this matter? Mr. Hooke answered, that some trials had been made about it; and that he would bring in an account of them in writing against the next meeting’ (Birch 3:58).

    6 November 1672, ‘Mr. Hooke read a discourse of his, containing his thoughts of the experiment of the quick-silver’s standing top-full, and far above the hight of twenty-nine inches; together with some experiments made by him, in order to determine the cause of the strange phaenomenon. He was ordered to prepare those experiments for the view of the society.
    There was also read a letter of Dr. Wallis to Mr. Oldenburg, dated Oxford October 25th, 1672, suggesting divers experiments for the elucidation of the same phenomenon: which letter was delivered to Mr. Hooke’ (Birch 3:59).
    Related fellows
    William Brouncker, 2nd Viscount Brouncker of Lyons (1620 - 1684, British) , Mathematician
    John Wallis (1650, British) , Mathematician
    Associated place
    <The World>
       > Europe
          > United Kingdom
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