Vaughan and Wordsworth stand pre-eminent among our English poets in being almost exclusively occupied with one theme, the mystical interpretation of nature.  Both poets are of a meditative, brooding cast of mind; but whereas Wordsworth arrives at his philosophy entirely through personal experience and sensation, Vaughan is more of a mystical philosopher, deeply read in Plato and the mediaeval alchemists.  The constant comparison of natural with spiritual processes is, on the whole, the most marked feature of Vaughan’s poetry.  If man will but attend, he seems to say to us, everything will discourse to him of the spirit.  He broods on the silk-worm’s change into the butterfly (Resurrection and Immortality); he ponders over the mystery of the continuity of life as seen in the plant, dying down and entirely disappearing in winter, and shooting up anew in the spring (The Hidden Flower); or, while wandering by his beloved river Usk, he meditates near the deep pool of a waterfall on its mystical significance as it seems to linger beneath the banks and then to shoot onward in swifter course, and he sees in it an image of life beyond the grave.  The seed growing secretly in the earth suggests to him the growth of the soul in the darkness of physical matter; and in Affliction he points out that all nature is governed by a law of periodicity and contrast, night and day, sunshine and shower; and as the beauty of colour can only exist by contrast, so are pain, sickness, and trouble needful for the development of man.  These poems are sufficient to illustrate the temper of Vaughan’s mind, his keen, reverent observation of nature in all her moods, and his intense interest in the minutest happenings, because they are all manifestations of the one mighty law.

Vaughan appears to have had a more definite belief in pre-existence than Wordsworth, for he refers to it more than once; and The Retreate, which is probably the best known of all his poems and must have furnished some suggestion for the Immortality Ode, is based upon it.  Vaughan has occasionally an almost perfect felicity of mystical expression, a power he shares with Donne, Keats, Rossetti, and Wordsworth.  His ideas then produce their effect through the medium of art, directly on the feelings.  The poem called Quickness is perhaps the best example of this peculiar quality, which cannot be analysed but must simply be felt; or The World, with its magnificent symbol in the opening lines:—­

      I saw Eternity the other night,
    Like a great Ring of pure and endless light,
       All calm, as it was bright;
    And round beneath it, Time, in hours, days, years,
      Driv’n by the spheres,
    Like a vast shadow mov’d.[21]