principle some few suggestions may be made here. The aesthetic 

 action of symmetrical arrangement is really established beyond 

 all doubt. Now E. Mach l ) has drawn attention to the remarkable 

 fact that the symmetry of a figure with respect to a single plane 

 will immediately be noticed, if the plane of symmetry is a vertical 

 one; that in the event of its position being horizontal, however, 

 the symmetry of the figure does not make a very strong impression : 

 we can walk for many hours by the side of a lake, before our 

 attention is drawn to the fact that the image in the water is the 

 replica of the scenery itself. Vertical bilateral symmetry appears 

 to be the one naturally adapted to us, while apparently horizontal 

 is almost imperceptible to the observer. Mach tries to give an 

 explanation of this fact by drawing attention to the other, that 

 our visual apparatus itself possesses a vertical plane of sym- 

 metry. The right and the left eye are in their internal structure 



Fig.. 4. 



Diagram of two combined harmonic vibrations, obtained with an 

 elliptic pendulum. 



each other's mirror-images: the function of the one can 

 therefore not be substituted for that of the other, as appears if 

 one transposes the pictures of a stereoscopical photo. If we now 

 look through the stereoscope, a strange world is observed, in 

 which concave and convex are interchanged, and in which all 



Berlin, (1901) pag. 121, 130, 135; Cf. also: Owen Jones, "The Grammar of Orna- 

 ment", London, (1868); J. L. Soret, "Sur les Conditions physiques de la Perception 

 du Beau", Geneve, (1892). 



x ) E. Mach, "Populdr-wiss. Vorlesungen, (1893), pag. 100; "Die Analyse der 

 Empfindungen" , 2e Aufl., (1900), pag. 81, 82, 85, 116. 



