52 THROUGH GLADE AND MEAD. 
circles owe their existence and present location to it. 
A difference of a few degrees, more or less, in this angle 
would have made the history of the world different. 
Civilization appears to depend upon it. Organic life, 
vegetable and animal, is deeply affected by the apparent 
northward or southward progress of the sun. Buds swell 
and open at its coming, and the birds, the welcome, joy- 
ous birds, herald its return. Scarcely has the sun crossed 
the Equator on its northward journey before the migra- 
tory birds are with us, and by the time it has reached 
the Tropic of Cancer they are all in their summer homes 
and are brooding over their nests, impelled by that 
mysterious inherited memory or instinct which leads 
them to do as their ancestors have done for ages, no 
one knows how long. When the sun has reached the 
Equator on its southern journey the fall migrations are 
beginning, and long before it has reached the Tropic of 
Capricorn the last of the summer visitants has bidden 
us adieu. They came arrayed in their gayest colors 
and singing their sweetest songs: they have gone with 
faded colors and almost in silence. We know they will 
come back, but we do not await their return with the 
same reverent feeling with which our ancestors in the old 
time awaited the coming of spring. The flight of the 
seasons affects us but little. We are as comfortable in 
winter as in summer, thanks to the improvements with 
which an advancing civilization has enriched our homes. 
