"As in music all notes have their own expression, and combinations of them have such diversity of effect upon the mind, may not the analogy hold good with regard to colours? Has not every colour its own character? And have not combinations of them effects similar to certain combinations in sounds? This is a subject well worth the attention of any one who has leisure and disposition to take it up: and I am persuaded that the old masters either worked from a knowledge of this art, or had such an instinctive perception of it, that it is to be discovered in their works. Suppose a painter were to try various colours on boards, and combinations of them--place them before him separately with fixed attention, and then examine the channels into which his thoughts would run. If he were to find their character to be invariable, and peculiar to each of the boards put before him, he would learn that before he trusts his subject to the canvass, he should question himself as to the sentiment he intends it to express, and what combination of colours would be consentient or dissentient to it. "This will certainly account for the colours of the old (particularly the historical) painters being so much at variance with common nature, sometimes glaringly at variance with the locality and position of the objects represented." "This knowledge of the effect of colours is certainly very remarkable in the Bolognese school. Who ever saw Corregio's backgrounds in nature, or indeed the whole colour of his pictures, including figures? Examine his back-ground to his Christ in the garden--what a mystery is in it! The Peter Martyr, at first sight, from the charm of truth that genius has given to it, might pass for the colour of common nature; but examine the picture as an artist, and you will come to another conclusion, and you will the more admire Titian."