For him life was a series of impressions, and the poet's duty was to recapture those impressions, to isolate them and brood over them, till gradually as a result of his contemplation emotion stirred again--an emotion akin to the authentic thrill that had excited him when the impression was first born in experience. Then poetry is made; this emotion "recollected" as Wordsworth said (we may add, recreated) "in tranquillity" passes into enduring verse. He treasured numberless experiences of this kind in his own life. Some of them are set forth in the _Prelude_, that for instance on which the poem _The Thorn_ in the _Lyrical Ballads_ is based; they were one or other of them the occasion of most of his poems; the best of them produced his finest work--such a poem for instance as _Resolution and Independence_ or _Gipsies_, where some chance sight met with in one of the poet's walks is brooded over till it becomes charged with a tremendous significance for him and for all the world. If we ask how he differentiated his experiences, which had most value for him, we shall find something deficient. That is to say, things which were unique and precious to him do not always appear so to his readers. He counted as gold much that we regard as dross. But though we may differ from his judgments, the test which he applied to his recollected impressions is clear. He attached most value to those which brought with them the sense of an indwelling spirit, transfusing and interpenetrating all nature, transfiguring with its radiance, rocks and fields and trees and the men and women who lived close enough to them to partake of their strength--the sense, as he calls it in his _Lines above Tintern Abbey_ of something "more deeply interfused" by which all nature is made one. Sometimes, as in the hymn to Duty, it is conceived as law. Duty before whom the flowers laugh, is the daughter of the voice of God, through whom the most ancient heavens are fresh and strong. But in most of his poems its ends do not trouble; it is omnipresent; it penetrates everything and transfigures everything; it is God. It was Wordsworth's belief that the perception of this indwelling spirit weakened as age grew. For a few precious and glorious years he had the vision "When meadow, grove, and stream, The earth, and every common sight To me did seem Apparelled in celestial light, The glory and the freshness of a dream." Then as childhood, when "these intimations of immortality," this perception of the infinite are most strong, passed further and further away, the vision faded and he was left gazing in the light of common day. He had his memories and that was all. There is, of course, more in the matter than this, and Wordsworth's beliefs were inextricably entangled with the conception which Coleridge borrowed from German philosophy. "We receive but what we give" wrote Coleridge to his friend, "And in our life alone doth Nature live."