515. One very remarkable consequence of this is, that the rays of mutually complementary colours, successively lighting the same object, concurrently with the diffused daylight, give rise to _the same coloration_. 516. This may be proved thus:—Between two windows directly opposite to each other, admitting diffused daylight, place a white plaster figure in such a position that each half shall be lighted directly by only one of the windows. On completely intercepting the light of one of the windows, and hanging a coloured curtain before the other, the figure appears only of the colour of the curtain; but if we open the other window, so that the figure is lighted by diffused daylight, while it is at the same time lighted by the coloured light, we then perceive some parts white, and some parts tinted with the complementary of the coloured light transmitted by the curtain. 517. This experiment, then, teaches us, that if a bonnet, rose-coloured, for example, give rise to a reflection of this colour on a complexion, the parts thus made rosy by the effect of contrast, themselves give rise to green tints, since the figure, while it receives rosy reflections, receives also diffused daylight. 518. To consider the real influence of the bonnet, we place three white plaster casts of the same model in a position equally illuminated by daylight; then observe them comparatively, after having clothed the middle cast with a white bonnet, and the two others with bonnets of which the colour of one is complementary to that of the other. _In this way we may satisfy ourselves that the influence of reflection in colouring a figure is very feeble, even when the bonnet is placed in the most favourable manner for observing the phenomenon._ 519. _Rose-coloured Bonnet._—Rose colour reflected upon the skin is very feeble, except on the temples; wherever the rosy parts are contiguous to parts feebly lighted by daylight, the latter will appear very lightly tinged with green. 520. _Green Bonnet._—Green colour reflected upon the skin is very feeble, except on the temples; wherever the green parts are contiguous to parts feebly lighted by daylight, the latter will appear slightly rosy; the effect of green in colouring it rose, is greater than the effect of reflected rose in colouring it green. 521. _Yellow Bonnet._—Yellow colour reflected upon the skin is very feeble, except on the temples; wherever the yellow parts are contiguous to parts feebly illuminated by daylight, the latter will appear very sensibly violet. 522. _Violet Bonnet._—Violet colour reflected on the skin is very feeble, even on the temples; wherever the violet parts are contiguous to parts feebly illuminated by daylight, the latter will appear slightly yellow; but this coloration is very feeble, because the reflections of violet have it themselves.