CHAPTER III 



THE BLUE SKY 



THE two great expanses, the blue ocean at 

 our feet and the blue sky over our heads, are 

 both impressive in vastness the ocean more 

 than the sky, possibly because we are familiar 

 with its extent and have felt its power. We 

 know, in a vague way, that the sky is even 

 vaster than the sea, that it is the open field 

 leading into interminable space ; but its very 

 obvious coloring, its apparent arch on all sides 

 springing upward and inward from the horizon, 

 its fixity, give us something of a false impres- 

 sion. We are inclined to regard it as a great 

 blue dome or roof, a something tangible that 

 is supported by the horizon-rim, a concave sur- 

 face looked at instead of a vast transparency 

 looked through. 



And there is some excuse for our regarding 



the blue sky as an actual surface. It is the 



outer envelope of the globe, and is made up of the 



blue rays of the sun reflected from atmospheric 



47 



Impret- 



tiontofthe 



iky. 



