In March, 1915, Frost came back to America—to a hill outside of Franconia, New Hampshire, to be precise. _North of Boston_ had been published in the United States and its author, who had left the country an unknown writer, returned to find himself famous. _Mountain Interval_, containing some of Frost’s most beautiful poems (“Birches,” “An Old Man’s Winter Night,” “The Hill Wife”), appeared in 1916. The idiom is the same as in the earlier volumes, but the notes are more varied, the convictions are stronger. The essential things are unchanged. The first poem in Frost’s first book sums it up: They would not find me changed from him they knew— Only more sure of all I thought was true. The fanciful by-play, the sly banter, so characteristic of this poet, has made his grimness far less “gray” than some of his critics are willing to admit. This elfin whimsy winks through the broad bucolic humor of “The Cow in Apple Time,” the mock pity of “The Road Not Taken,” the tenderness of “The Runaway” and the lovely apostrophe to an orchard in “Good-Bye and Keep Cold.” Frost taught at Amherst College from 1916 to 1919, but found that his association with scholastic life took too much of his creative energy. In 1920, therefore, he bought a few acres in Vermont and devoted himself once more to the double labors of farmer and poet. Through his lyrics as well as his quasi-narratives, he has uttered (and is voicing) some of the deepest and richest notes in American poetry. MENDING WALL