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.

    42/48 page 40
    This fieve being then lighted, if we look over, the folid parts of it will appear yellow, as they ufed to do. But the tranfmitfedrays, which pafs through the holes, undergo at once a reflection, a refraction, and a decreafe; and as the refrac¬ tion in blue is the mofc apparent in a de- ereafed light, the refraCted rays, mixed with the reflected ones by the edges of the holes, produce the green. Although this experiment is of no confe- quence in the prefent differtation, I made a particular analyfis of it, in order to fhow how exaCt we mult be in our operations; and how well acquainted with the materials that we make ufe of, as well as of the mechanifm of their aCtion. We fhall end this differtation with an ex¬ periment of this kind, which, for want of examination, has been admitted as a rule in optics. EXPERIMENT XXVI. I take three crayons of paftel; a blue, a red, and a yellow one; all three in the fame degree of fliade, or as nearly fo as the eye can judge, and of a good ftrength of colour. I reduce them feparately to a fmall powder. I take nine parts of the blue powder, and eight parts of the red, and mix them exactly.
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