Fitness of the parts to the design for which every individual thing is form'd, either by art or nature, is first to be consider'd, as it is of the greatest consequence to the beauty of the whole. This is so evident, that even the sense of seeing, the great inlet of beauty, is itself so strongly bias'd by it, that if the mind, on account of this kind of value in a form, esteem it beautiful, tho' on all other considerations it be not so; the eye grows insensible of its want of beauty, and even begins to be pleas'd, especially after it has been a considerable time acquainted with it. It is well known on the other hand, that forms of great elegance often disgust the eye by being improperly applied. Thus, twisted columns are undoubtedly ornamental; but as they convey an idea of weakness, they always displease, when they are improperly made use of as supports to any thing that is bulky, or appears heavy. The bulks and proportions of objects are govern'd by fitness and propriety. It is this that has establish'd the size and proportion of chairs, tables, and all sorts of utensils and furniture. It is this that has fix'd the dimensions of pillars, arches, &c. for the support of great weight, and so regulated all the orders in architecture, as well as the sizes of windows and doors, &c. Thus though a building were ever so large, the steps of the stairs, the seats in the windows must be continued of their usual heights, or they would lose their beauty with their fitness: and in ship-building the dimensions of every part are confin'd and regulated by fitness for sailing. When a vessel sails well, the sailors always call her a beauty; the two ideas have such a connexion! The general dimensions of the parts of the human body are adapted thus to the uses they are design'd for. The trunk is the most capacious on account of the quantity of its contents, and the thigh is larger than the leg, because it has both the leg and foot to move, the leg only the foot, &c. Fitness of parts also constitutes and distinguishes in a great measure the characteristics of objects; as for example, the race-horse differs as much in quality, or character, from the war-horse, as to its figure, as the Hercules from the Mercury. The race-horse, having all its parts of such dimensions as best fit the purposes of speed, acquires on that account a consistent character of one sort of beauty. To illustrate this, suppose the beautiful head and gracefully-turn'd neck of the war-horse were placed on the shoulders of the race-horse, instead of his own aukward straight one: it would disgust, and deform, instead of adding beauty; because the judgment would condemn it as unfit. [Illustration: Fig. 3]