Theory of colours and vision. / By G. Palmer.

  • George Palmer
Date:
MDCCLXXVII. [1777]
Catalogue details

Licence: Public Domain Mark

Credit: Theory of colours and vision. / By G. Palmer. Source: Wellcome Collection.

    43/48 page 41
    RESULT. The mixture is purple. EXPERIMENT XXVII. I add to this mixture feven parts of yellow. RESULT. The mixture appears grey. JOHNSON. And why not black, as the piece of cloth did? PALMER. j * / Eecaufe every one of thefe colours brings its white particles, by which it is feen ; and, as they cannot be deftroyed, they produce the grey, by reflecting to the eye a light uniformly gltered by the proportionate mixture of the three colouring principles. When the founders and followers of the old fyftem intended to prove the compolition .of the white by the re-union of the primitive colours, they mixed together cinnabar, ver- degris, purple, mountain blue, and other light colours. This mixture produces a weak greys but the caufe of it being abfolutely in¬ explicable on their principles, and as they were obliged to adapt this experiment to their fyftem, they removed themfelves to the diftance of eighteen feet, to look at this grey powder; and being not able to diftinguiih it there from a white paper, they concluded that
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