Poetry is the sea in which the soul of man can swim even as butterflies can swim in the air, or happy ghosts swim in the finer element of the infinite ether.

The last three stanzas of the poem are very suggestive: And meantime, yonder streak Meets the horizon's verge; That is the land, to seek If we tire or dread the surge: Land the solid and safe-- To welcome again (confess!) When, high and dry, we chafe The body, and don the dress.
Does she look, pity, wonder At one who mimics flight, Swims--heaven above, sea under, Yet always earth in sight?
"Streak," meaning an indistinct line, here refers to the coast far away, as it appears to the swimmer.

It is just such a word as a good Japanese painter ought to appreciate in such a relation.

In suggesting that the swimmer is glad to return to shore again and get warm, the poet is telling us that however much we may talk about the happiness of spirits in heaven--however much we may praise heaven in poetry--the truth is that we are very fond of this world, we like comfort, we like company, we like human love and human pleasures.

There is a good deal of nonsense in pretending that we think heaven is a better place than the world to which we belong.