Seek them first of all in a weakening of literary tradition. The sky changes, not the mind, said Horace, but this is true only of the essentials of being. The great writers of our common English tradition--Chaucer, Shakespeare, Milton, and many others--are as good for us as they are good for you. It is even whispered that our language is more faithful to their diction than is yours. But the conditions of life in a new environment bring a multitude of minor changes with them. To begin with little things, our climate, our birds, our trees, our daily contact with nature, are all different. Your mellow fluting blackbird, your wise thrush that sings each song twice over, your high-fluttering larks we do not know. Our blackbird creaks discordantly, our plaintive lark sings from the meadow tussock, our thrush chimes his heavenly bell from forest dimness. And this accounts, may I suggest in passing, for the insistence upon nature in American writing, from Thoreau down. Our social and economic experience has been widely different also; and all this, plus the results of a break in space and time with the home country of our language, weakened that traditional influence which is so essential for the production of a national literature. It had to be; good will come of it; but for a time we vacillated, and we still vacillate, like a new satellite finding its course. Again, the constant shift of location within America has been a strong delaying factor. Moving-day has come at least once a generation for most American families since the days of William Penn or _The Mayflower_, The president of a Western university, who himself, as a baby, had been carried across the Alleghenies in a sling, once told me the history of his family. It settled in Virginia in the seventeenth century, and moved westward regularly each generation, until his father, the sixth or seventh in line, had reached California. On the return journey he had got as far as Illinois, and his son was moving to New York! The disturbing effect upon literature of this constant change of soils and environment is best proved by negatives. Wherever there has been a settled community in the United States--in New England of the 'forties and again in the 'nineties, in the Middle West and California to-day--one is sure to find a literature with some depth and solidity to it. The New England civilization of the early nineteenth century, now materially altered, was a definable culture, with five generations behind it, and strong roots in the old world. From it came the most mature school of American literature that so far we have possessed.