So THE PROBLEM OF THE GALLOPING HORSE 



moon drawn of a little more than a quarter of an inch 

 broad), a post or a man six feet high drawn on the canvas 

 as three inches high absolutely and definitely means that 

 that man or post is sixty feet away from the observer 

 inside the picture. The height of the represented object 

 is the same fraction of the real object as the eye-to-frame 

 distance is of the distance of the observer to the real object. 

 If by a two-inch moon the artist has thrown you back from 

 the front plane of the scene to a distance of nineteen feet, 

 then the six-foot post or man drawn as three inches high 

 definitely asserts that it or he is 456 feet distant within 

 the picture. So, too, if the church tower which cuts the 

 moon is really sixty feet high and is drawn of two inches 

 vertical measure in the picture, it is an assertion when 

 the moon is represented one quarter of an inch broad 

 that the church tower is 290 yards, or a sixth of a mile 

 distant. If, on the other hand, other things remaining the 

 same, the moon is drawn two inches in diameter, the church 

 tower is now asserted to be eight times as far off, or about 

 a mile and a third. Very generally these facts are not 

 considered by painters. They represent the low moon (or 

 sun) big because the erroneous mental impression is common 

 to all of us that it is big that is, bigger, much bigger, 

 than the high moon or sun, and they do not follow out 

 the consequences in perspective of the pictorial increase 

 of the moon's apparent diameter. 



If we could ascertain why it is that the low moon pro- 

 duces a false impression of being bigger as a mere disc 

 in the scene than does the high moon, we might be able 

 to discover how an artist could produce, as Nature does, 

 an impression or belief in its greater size whilst keeping 

 it all the time to its proper size. The explanation of the 

 illusion as to the increased size of the sun's or moon's disc 

 when low, given by M. Flammarion and other astronomers, 

 is that the low sun or moon is unconsciously judged by us 



