772 POPULAR SCIENCE MONTHLY. 



production, may have been or is almost wholly ignored. We are 

 ceasing to treat the soil as a mine subject to exhaustion, but we have 

 as yet made only a beginning in treating it as an instrument of pro- 

 duction which will for a long period respond in its increasing product 

 in exact ratio to the mental energy which is applied to the cultivation 

 of the land. 



THE COMING OF THE CATBIRD. 



Br SPENCEE TROTTER. 



T"N southeastern Pennsylvania there comes a day in February that 

 -L brings with it an indefinable sense of joyousness. A southerly 

 wind wanders up the Delaware with a touch of the spring in its air 

 that quickens, for the first time, the slumbering life. It is then that 

 those mysterious forces in the cells of living things begin their subtle 

 work — hidden in the dark, underground storehouses of plants and the 

 sluggish tissues of animals buried in their winter sleep. On such 

 a day the ground hog ventures from his burrow, some restless bee is 

 lured from the hive to wander disconsolate over bare fields, a snake 

 crawls from its hole to bask awhile in the sunshine, and one looks 

 instinctively for the first breaking of the earth that tells of the early 

 crocus and the peeping forth of daffodils. The southerly wind is 

 more apt than not to be a telltale, for with all its springtime softness 

 it is drawing toward some storm center, near or remote, that will in- 

 evitably follow with rough weather in its sweep. The country folk 

 rightly call such a day a " weather breeder," and even the ground hog 

 knows its portent in the very sign of his shadow. Come as it will, 

 the day is really a day borrowed in advance from the spring, as though 

 to hearten one through all the dreary days that will follow and, in 

 starting the growing forces of vegetation, to make ready for the sea- 

 son's coming. 



With this forerunner of the year come the harbingers of the bird 

 migration. With the rise of the temperature to sixty or over, a well- 

 marked bird wave from the south spreads over the Delaware Valley. 

 On this balmy, springlike day we hear for the first time since Novem- 

 ber the croaking of grackles as a loose flock wings overhead or 

 scatters among the tree tops. A few robins may show themselves, 

 and the mellow piping of bluebirds lends its sweet influence to 

 the charm of such a day. There is a sense of uncertain whereabouts 

 in the bluebird's note, a sort of hazy, in-the-air feeling that suggests 

 sky space. It does not seem to have the tangible element by which 

 we can locate the bird as in the voices of the robin and the song spar- 

 row. It is on such a day as this that song sparrows are first heard — 



