"Both Albert Durer and Lomazzo, who wrote on painting, had this conceit; and so much was Père Castle, a French theoretical doctor, impressed with the idea, that with infinite pains and trouble he contrived a harpsichord to play _harmonious composition of colours_! On this he wrote a book, and built a system in which prism colours were his notes; these the keys of his instrument were to produce at pleasure. But surely he could not have been drawn into such an absurdity without having first persuaded himself that colours and sounds were of the same nature, and that the like disposition of them both would answer the same purpose, _i.e._ that a jig in notes would be a jig in colours.[67] I should not be much surprised if some native of that nation of _taste_ contrived an instrument for cookery on a similar plan.[68] This would without doubt be adopted in England, where it must unquestionably have great encouragement. How pleasant would it be to mark Monsieur de Quisiney at his harpsichord, composing a grand festino for the entertainment of foreign ministers; and would the inventor compose a banquet for an installation, or a feast for a Lord Mayor's day, it would ensure him the hearts of both courtiers and citizens. What delight would it afford to a certain eminent composer to see his two favourite sciences thus united![69] "The fact is, that though compositions of music and colours may illustrate each other in their principles, they very essentially differ in their effects. The notes on a scale in music will range similar to the colours in a rainbow, or to those separated by the prism, but their operations are precisely opposite. "For example, let all the keys of an harpsichord be pressed down at one stroke, and the ear will be offended with harsh, jarring, and confused sounds; but if you run your fingers along them in succession, it produces a sort of harmony. In colours it is directly the reverse; for though the varied hues of the rainbow strike the eye agreeably at first sight, yet were flickering colours to follow each other in quick succession, the optic nerve would suffer pain in proportion as the tints were more or less vivid, and played in quick or slow time." These observations are followed by some hints on easy deportment, and succeeded by the following desultory thoughts, which in his manuscript Hogarth entitles "A Supplementary Chapter on Dress:"--