66 THE POPULAR SCIENCE MONTHLY 



mechanism of ocular fixation must carry out its movements with an 

 ease or effort determined by the external configuration brought into at- 

 tention. It has been shown that in oblique movements of the eyes 

 there is a definite rotatory movement of the globes, so that in following 

 any line departing obliquely from the prime axis of vision it seems 

 obvious that the fixation mechanism would suffer less fatigue when this 

 line is curved objectively to correspond with the normal rotation round 

 the visual axis. In following oblique lines which are objectively 

 straight the fixation mechanism must be continually harrassed by the 

 voluntary effort to maintain the contemplated line in the horopter. 



No homily is needed to convince the modern physician of the para- 

 mount psychological importance of the motor sensations arising from 

 the coordinations of the external eye muscles. As sensory disasters 

 from eyestrain often result in muscular unbalance, it is not difficult to 

 believe, conversely, that peculiar advantages may spring from unob- 

 trusive objective aids to the action of the intricate machinery of fix- 

 ation whereby the eye is enabled to rove over a picture without con- 

 scious effort. According to this view, then, the curved lines of the 

 Parthenon are psychologically straight to the onlooker in so far as they 

 parallel the normal inclination of the after-image in oblique vision. It 

 is easy to believe that the physiological result of such relations is rest, 

 absence' of fatigue. But kind nature repays subconscious physiological 

 coordination in a rich and peculiar way; the thing so seen and under- 

 stood without effort arouses a new class of ideas — an esthetic feeling — 

 beauty. 



It may be objected to the foregoing argument that, though the out- 

 line of one side of a column may by reason of its curve allow the eye to 

 glance along it without the effort of fixation, that of the opposite side, 

 forming a reciprocal arc, must simultaneously offer an equally exag- 

 gerated impediment to ease of vision. I answer that the percipient 

 mind tends to neglect all sensory impressions which interfere with the 

 homogeneity of a mental picture. The infinite details of a landscape 

 impressed upon the outskirts of the retina? give rise for the most part 

 to mental double images, but these in no wise disturb the acuteness of 

 vision for an object projected on the retinal fovea?. Moreover, it is not 

 intended here to imply that the idea elaborated above contains the 

 whole physiologic basis of the esthetic charm of the Parthenon. In- 

 deed, the author of the admirable paper 10 which has been quoted, whose 

 thesis, by the way, ascribes the preeminence of Greek art to its foun- 

 dation on physiological principles, himself gives other interpretations 

 to the psychic impression produced by the temple. These explanations, 

 however, do not displace, but rather complement that detailed above. 



In the foregoing discussion evidence has been offered along two 



10 Edinburgh Beview, loc. cit. 



