abstract impression of the existence of shade; but, as the duration of shade, so is the fear of melancholy excited by it. Consequently, when we wish to increase the abstract impression of the power of any influence over objects with which we have no connexion, we must increase degree; but, when we wish the impression to produce a permanent effect upon ourselves, we must increase duration. Now, degree is always increased by contrast, and duration by assimilation. A few instances of this will be sufficient. Blue is called a cold colour, because it induces a feeling of coolness to the eye, and is much used by nature in her cold effects. Supposing that we have painted a storm scene, in desolate country, with a single miserable cottage somewhere in front; that we have made the atmosphere and the distance cold and blue, and wish to heighten the comfortless impression. There is an old rag hanging out of the window: shall it be red or blue? If it be red, the piece of warm colour will contrast strongly with the atmosphere; will render its blueness and chilliness immensely more apparent; will increase the degree of both, and, therefore, the abstract impression of the existence of cold. But, if it be blue, it will bring the iciness of the distance up into the foreground; will fill the whole visible space with comfortless cold; will take away every relief from the desolation; will increase the duration of the influence, and, consequently, will extend its operation into the mind and feelings of the spectator, who will shiver as he looks. Now, if we are painting a picture, we shall not hesitate a
