The 'barn and byre' (line 3) must have belonged to Newfield, the only farmhouse in the foreground.
The 'spouting mill' (line 3) is now a ruin. In Wordsworth's time it was in full work. Later (in the autumn of 1842), when it was visited by James Thorne, the wheel was broken, the machinery decaying, and the roof partly fallen in. At the present time, wheel, machinery, and roof have totally disappeared, and there is nothing to indicate that it ever was a mill. It was only by inquiring of the older inhabitants that I learnt these ruined walls standing by the Beck represent that 'mill for spinning yarn,' of which Wordsworth says that it calls to mind 'the momentous changes wrought by such inventions in the frame of society.' The ruin stands on the Tarn Beck, a few yards below Seathwaite Chapel, and on the other side of the stream.
The last three lines of the sonnet,
While the warm hearth exalts the mantling ale, etc.,
are probably an allusion to the Inn which, in Wordsworth's time, was to be found here. This is now a farmstead. It is called Newfield, and is just below Seathwaite Chapel. In Wordsworth's day it was inn and farm combined.
Mr. Malleson, in the article quoted above, appears (p. 576) to regard the green slope ascending towards Seathwaite Tarn, which opens on the left about a mile before the traveller reaches Seathwaite Chapel, as the 'Open Prospect'; but, though the fields here are certainly 'sprinkled o'er with dwellings,' the juxtaposition of the 'hamlet,' the 'barn and byre,' and the 'spouting mill' is wanting, and the allusion to the inn loses its point." (Herbert Rix.)
"It may be of interest to know that still the Newfield farm (in Wordsworth's time farm and inn combined) keeps up the well-deserved description of the poet. It is still 'a generous household.' When the yeoman, who was the last innkeeper and farmer combined, was on his death-bed, he enjoined those to whom Newfield passed to remember that 'though the license was to drop, and it was to become a private house, yet no stranger in the valley who requested a night's lodging was ever to be refused,' and the generous household are proud to keep up the tradition of hospitality." (H. D. Rawnsley.)
[FM] Compare Virgil, Æneid iii. 23—
Densis hastilibus horrida myrtus.
(W. G. Rushbrooke.)