Fond as ever of wandering, Shelley set out in the early summer for a
tour with Mary. They visited Devonshire and Clifton, and then settled in
a house on Bishopsgate Heath, near Windsor Forest. The summer was
further broken by a water excursion up the Thames to its source, in the
company of Mr. Peacock and Charles Clairmont. Peacock traces the poet's
taste for boating, which afterwards became a passion with him, to this
excursion. About this there is, however, some doubt. Medwin tells us
that Shelley while a boy delighted in being on the water, and that he
enjoyed the pastime at Eton. On the other hand, Mr. W.S. Halliday, a far
better authority than Medwin, asserts positively that he never saw
Shelley on the river at Eton, and Hogg relates nothing to prove that he
practised rowing at Oxford. It is certain that, though inordinately fond
of boats and every kind of water--river, sea, lake, or canal--he never
learned to swim. Peacock also notices his habit of floating paper boats,
and gives an amusing description of the boredom suffered by Hogg on
occasions when Shelley would stop by the side of a pond or mere to float
a mimic navy. The not altogether apocryphal story of his having once
constructed a boat out of a bank-post-bill, and launched it on the lake
in Kensington Gardens, deserves to be alluded to in this connexion.

On their return from this river journey, Shelley began the poem of
"Alastor", haunting the woodland glades and oak groves of Windsor
Forest, and drawing from that noble scenery his inspiration. It was
printed with a few other poems in one volume the next year. Not only was
"Alastor" the first serious poem published by Shelley; but it was also
the first of his compositions which revealed the greatness of his
genius. Rarely has blank verse been written with more majesty and music;
and while the influence of Milton and Wordsworth may be traced in
certain passages, the versification, tremulous with lyrical vibrations,