42 



NATURE FOR ITS OWN SAKE 



in shadow or, at least, an error to suppose 

 that it is always apparent to ns. There are in- 

 fluences, too, such as the local color of the 

 ground and the sky reflection, that may neutral- 

 ize or utterly destroy the complementary hue. It 

 might be thought that a yellow sun at midday 

 would produce blue shadows under the green 

 maple on the lawn, but as a matter of fact it 

 does not. The color of the shadow, whatever 

 it may be, is absorbed and lost in the green of 

 the lawn upon which it falls. The same tree 

 shadow falling on pale-gray clay, or across a 

 sandy road, will show blue or lilac at once ; 

 but I do not think this is owing necessarily to 

 the presence of the complementary hue. It is 

 more likely caused by sky reflection, helped 

 out, perhaps, by atmospheric reflections from 

 the sides. 



The blue shadows upon snow, so common 

 in winter, are never seen except under a blue 

 sky ; and the bluer the sky the more apparent 

 the blue in the shadow. They are produced 

 by sky reflection, and the sky coloring is faintly 

 apparent on the snow in full sunlight, but more 

 obvious, of course, in the shadow. These blue 

 shadows are stronger at sunrise and at sunset 

 than at any other time. Under a clouded 



