"It would be foreign to the subject of the present memoir, to consider the beauty of expression of the human countenance; although this species of beauty is in a great degree referrible to muscular action. That muscular action which belongs to the present topic is not that of the object, but that of the observer. It may be scarcely necessary again to disclaim any design of giving a complete analysis of beauty in general, or to repeat the concession that man's notions of beauty are modified by various associations. "_Final Cause._--The benevolence of the Author of nature is strikingly manifested in connecting present pleasure with obedience to the natural laws. It has been shown that vision is attended with muscular action which is generally pleasurable. If seeing had required no muscular action, we should have wanted one of our present stimuli to the acquisition of knowledge. This stimulus is especially necessary in infancy, and then powerfully prompts to observation, even anterior to the dawnings of intellectual curiosity, with which it subsequently co-operates. We see, in this arrangement, the exemplification of a principle which extensively pervades the laws under which we are placed by the Creator--which is, that mental attainments, as well as other acquisitions, shall require action; and that action shall be attended with pleasure. Whether the acquisition is to be made by the manual labor of the artisan, by the manipulations of the artist, the chymist, or the experimental philosopher, by the sedentary student of books, or by the observer of natural phenomena in his original survey of the universe--in every case it is muscular action.