636. Finally, to notice the effect which associations of ideas have on our opinions. For example, he who arrives at Versailles, full of admiration for the age of Louis XIV., repeoples the gardens with all the great men that have frequented them, and his thoughts recurring to the _fêtes_ given by an elegant and polished court, the admiration of Europe, he will judge the work of Lenôtre more favourably than he who, without being hostile to the _grand siècle_, will see nothing but a garden subordinate to a palace. And the Christian who associates in his mind the architectural form, the brilliancy of the coloured glass, and the religious ceremonies of the Gothic Church, all which he has venerated from his childhood, will be in a disposition to prefer the cathedral of Cologne to that of St. Peter’s at Rome; while the latter would be associated with the profoundest veneration in the mind of a Christian of Rome. ON THE COLOURS OF MILITARY UNIFORMS. The following section, in which are described the advantages of contrast with regard to the heightening and purifying of the colour of cloths for dress, properly belongs to the chapters on clothing, pp. 165, &c. But, as in the present day, the colours of men’s ordinary dress are not usually very various or strongly contrasted, this portion of the work has a more special application to military uniforms; the choice of colours being regulated by the principles laid down and exemplified throughout the work. And, independently of economical considerations, the selection and arrangement of colours for military uniforms demand investigation as to the prominence or obscurity resulting from their combination, as well as to their æsthetical effect. _Of Uniforms composed of Complementary Colours._ By the law of contrast, red and green of similar tone in the same uniform, will heighten each other. Let us suppose the augmentation of colour by juxtaposition to equal one-tenth, its optical effect may be stated as 1¹/₁₀. If a single coloured uniform, by one year’s wear lose one-tenth of its colour, it is clear that the uniform of the above two colours after being worn the same time will be as effective as the single colour was originally. Similar reasoning may be applied to all colours that are complementary, as orange and blue, violet and greenish yellow, &c.; it is necessary however to take into consideration their difference of tone. Among colours which are not complementary, but which produce an agreeable contrast, may be mentioned particularly blue and yellow, blue and scarlet, green and yellow.