Credit: ©The Royal Society
    Image number: RS.14328

    Generation of a hyperbolical cylindroid

    Date
    10 June 1669
    Creator
    Unknown, Artist
    Object type
    Archive reference number
    Manuscript page number
    p71
    Material
    Dimensions
    height (page): 360mm
    width (page): 230mm
    Subject
    Description
    On 10 June 1669, Wren presented to the Royal Society his idea that a machine for grinding hyperbolical lenses could be developed from the principle that the axis of a cylinder was a hyperbolic surface; this was ordered to be registered and was duly entered in the Register Book here. Robert Hooke was asked to make a machine based on Wren's design, but it appears he never made one. Wren hinted at the idea of a machine in Philosophical Transactions vol. 4, no. 48 (June 1669), which was followed by another figure (Cl.P/1/11/001a (previously 11a)) published later that year in Philosophical Transactions vol. 4, no. 53.
    Object history
    At the meeting of the Royal Society on 10 June 1669, ‘Dr. Christopher Wren explained the model of his engine for grinding hyperbolical glasses, viz. upon what geometrical principle it depends, and how that is to be applied to practice. The president affirmed, that he had considered the principle, it being formerly imparted to him, and had found it mathematically true; and as to its application to use, the success of that depended on experiment. The contrivance was, that in this engine there was a complication of three different motions, whereby three bodies so work upon another, as to produce an hyperbolical figure; any irregularity, by the encountering of one another, being immediately rectified. Dr. Wren intimated, that great care must be had in setting the engine, that being somewhat nice, since the three axes must all intersect in a point, and one at the right angles with the other two. It was ordered, that the paper containing the demonstrations of this should be registered, and an engine be made by the care of Mr. Hooke, to try the principle of the matter’ (Birch 2:379).

    17 June 1669, ‘Mr. Hooke excused himself for having prepared no experiments for this meeting. He was ordered to take care, that against the next either his own new instrument for working elliptical glasses, or that of Dr. Wren for grinding hyperbolical ones, might be ready’ (Birch 2:383).

    C. Wren, 'The generation of an hyperbolical cylindroid demonstration and the application thereof for grinding hyperbolical glasses hinted at', Phil. Trans. vol. 4, no. 48 (June 1669), pp. 961-62, ref. to fig. I, 961-62.
    Related fellows
    Christopher Wren (1632 - 1723, British) , Architect
    Associated place
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