390 THE POPULAR SCIENCE MONTHLY 



Hudson and Connecticut. Spring is always appreciably earlier in 

 such places. It spreads later over the uplands. We are apt to think 

 of our rivers as flowing eastward to the ocean, when in reality they 

 flow almost directly southward. This is true, at least, of the more 

 northerly rivers — the Connecticut, Hudson, Delaware and Susque- 

 hanna, and of the larger rivers flowing into the Gulf of Maine, as the 

 Kennebec and the Penobscot. South of the Chesapeake the rivers do 

 come more directly from the west. 



The physical basis of this advent of spring is the northward move- 

 ment of a definite line of heat (the isotherm of 43.8 degrees F.) that 

 calls into germinal life the slumbering forces of vegetation, awakens 

 the hibernating animal and urges the migratory bird to seek its 

 northern nesting place. An expanding zone of green marks this 

 creeping of the vanguard of spring up river valleys, over hill country 

 and along mountain slopes until all the land is invaded and the frost 

 giant driven back to his hyperborean realm. In woods almost the 

 first touch of spring is seen when the branches of the spice-bush break 

 out in yellow blossoms. In fields, at this time, the plow is turning 

 over the fallow and the air is redolent of earthy smells. In gardens 

 the sod-breaking crocus and daffodil appear along the squalid, unkempt 

 borders. From meadow pools comes the piping chorus of cricket frogs. 

 Crows are brooding in remote woodlands, and the grackle flocks and 

 robins have returned. This is spring as we know it on the Atlantic 

 slope to-day and as our fathers knew it after the first planting of the 

 wilderness. 



Spring waxes into summer and summer wanes into autumn and 

 after the gorgeous pageant of the leaf has passed there steals over 

 this land a time of strange stillness. A haze, like the farthest waftings 

 of some distant forest smoke, broods over the landscape, veiling its 

 features and filling the responsive mind with a vague sense of mystery. 

 There is a mellowness of sight and sound; all that was harsh and dis- 

 cordant seems now blended into one harmonious tone by the enchanted 

 haze. All too soon these few delightful days are dispelled and we stand 

 upon the threshold of winter. This charming period, coming in 

 November, has been called the Indian Summer. The reason for its 

 name is not obvious. It suggests remoteness, like some old Celtic 

 tale, and there are those of us who would fain think of it as a heritage 

 from the aboriginal past. Students who have investigated the matter 

 will scarcely credit such vain imaginings, but however the name may 

 have come, it is surely most happily associated with a dreamy spell of 

 weather in the late days of the American autumn. 6 



VII 



The influence which this threshold of the new land had upon the 

 mind and character of the people is perhaps more apparent than are its 

 6 " The Term Indian Summer," a pamphlet by Albert Matthews, Boston. 



