says, that the surface of any opake body participates of the colour of any other body sending the light to it. Therefore white being deprived of the light of the sun by the interposition of any other body, will remain white; if exposed to the sun on one side, and to the open air on the other, it will participate both of the colour of the sun and of the air. That side which is not opposed to the sun, will be shaded of the colour of the air. And if this white were not surrounded by green fields all the way to the horizon, nor could receive any light from that horizon, without doubt it would appear of one simple and uniform colour, viz. that of the air.
Chap. CCXLV.—Of Colours.
The light of the fire tinges every thing of a reddish yellow; but this will hardly appear evident, if we do not make the comparison with the daylight. Towards the close of the evening this is easily done; but more certainly after the morning twilight; and the difference will be clearly distinguished in a dark room, when a little glimpse of daylight strikes upon any part of the room, and there still remains a candle burning. Without such a trial the difference is hardly perceivable, particularly in those colours which have most similarity; such as white and yellow, light green and light blue; because the light which strikes the blue, being yellow, will naturally
