Credit: ©The Royal Society
    Image number: RS.15122

    Observations on the burning glass

    Date
    17th century
    Creator
    Unknown, Artist
    Object type
    Archive reference number
    Manuscript page number
    p3
    Material
    Dimensions
    height (page): 190mm
    width (page): 150mm
    Subject
    Content object
    Description
    This document describes an experiment with a burning glass filled with smoke. It was observed that the smoke particles move very quickly in the light, and the author wonders whether all burning is made by such movement of particles.
    Transcription
    Observations on the Burninglass
    B. the burninglass
    BA. the light Pyramid.
    ? A ? The opac segment of the cylinder BC
    AC: the inlightned Pyramid
    CF the opac cylinder

    1. The light of a burninglass, impregnated with smoke, appears in the form above described.
    2. First, a Pyramidical body of light, BA, spinning round, with a rapid motion, to the left hand (that is, like top, set up left hand way) not terminating in a print, at the vertex A; but twisted round in a spiral worm, cylindrical; of a very violent motion; in which the may see the smoke somtimes twirld round downwards to C; & again returning upwards to B; like the twisting & untwisting of a spiral worm: & all the time one may observ particles of smoke cast of fiercely from it, like sand from a spirning top; the like in some measure from the whole Pyramid BA.
    3. The burning is not any wher in the spiral line A; but ther wher it is next B. nor till then, doe the light come to the smallest point becaus part of the enlightned Pyramid AC, mixes with the light of AB. as may be seen in the figure.
    4. I conceiv the inflammation is wrought by this spiral motion which twists together the particles of a body; & by squeezing or wringing, forces them from their flegm; which transpiring in smoke, the freed particles assume the nature of fire.
    5. Querie; Whether all burning be not made by such a terebration, or spiral motion. which will easily sole the shriveling of skin, being twisted or wrung together, as we wring a wet cloth. & the piercing nature of fire in general.
    Transcribed by the Making Visible project
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