has even been deep, and the sky by no means the lightest part of the picture, at twilight the whole landscape comes out too hard upon the sky, which with its colour has lost its tone, and become, with relation to the rest, by far too light. It is said that of all the pictures in the National Gallery, when seen at twilight, the Coreggios retire last--we speak of the two, the "Ecce Homo" and the "Venus, Mercury, and Cupid." In these there is no blue but in the drapery of the fainting mother, and that is so dark as to serve for black or mere shadow; the lighter blue close upon the neck is too small to affect the power of the picture. It certainly is a fact, that blue fades more than any colour at twilight, and, relatively speaking, leaves the image that contains it lighter. We should almost be inclined to ask the question, though with great deference to authority, is blue, when very light, necessarily cold; and if so, has it not an activity which, being the great quality of light, assimilates it with light, and thus takes in to itself the surrounding "radiance?" A very little positive warm colour, as it were set in blue, from whatever cause, gives it a surprising glow. We desire to see the theory of colours treated, not with regard to their corresponding harmony in their power one upon the other, nor in their light and shadow, but, if we may so express it, in their sentimentality--the effect they are capable of in moving the passions. We alluded to this in our last paper, and the more we consider the subject, the more we convinced that it is worth deeper investigation. * * * * *