hue. A powerful impression of light leaves the sensation of red on the retina. In the prismatic yellow-red which springs directly from the yellow, we hardly recognise the yellow.
701.
This deepening takes place again by means of colourless semi-transparent mediums, and here we see the effect in its utmost purity and extent. Transparent fluids, coloured with any given hues, in a series of glass-vessels, exhibit it very strikingly. The augmentation is unremittingly rapid and constant; it is universal, and obtains in physiological as well as in physical and chemical colours.
JUNCTION OF THE TWO AUGMENTED EXTREMES.
702.
As the extremes of the simple contrast produce a beautiful and agreeable appearance by their union, so the deepened extremes on being united, will present a still more fascinating colour; indeed, it might naturally be