During Wordsworth’s time this bon mot was widely attributed to Rousseau. See, for
instance, The Poetical Works of Anna Seward, II.101 (Edinburgh: Ballantyne, 1810).

The Lake District is in fact England’s wettest region. Precipitation varies within
its boundaries—Penrith, located in the Eden Valley, receives just 30-35 inches annually,
whereas Seathwaite in Borrowdale receives an average of 130-40—but the region overall
averages more than 80 inches. England as a whole averages around 33 inches per year,
so Wordsworth’s statement is essentially accurate.

Shakespeare, Measure for Measure III.i.9.

The bilberry is a low-growing shrub with edible berries, known in English by many
local names.

Jonathan Carver (1732-1780) was an American explorer and travel writer. Wordsworth
has in mind a description from Carver’s Travels through the Interior Parts of North America (1778) in which the author reports on exploring the shore of Lake Superior (pp. 132-33).

The phrase comes from Virgil’s Georgics II.469 and suggests natural lakes of fresh water (as opposed to artificial reservoirs
or ponds). Other writers on landscape, including Gilpin, use this locution as well.

Wordsworth quotes from Walter Savage Landor’s Idyllia Heroica Decem, Librum Phaleuciorum Unum (Heroic Idylls), first published in Pisa in 1820. Owen and Smyser report that Landor had recently
published an essay defending Wordsworth from his critics, so it appears that Wordsworth
was returning a favor by praising Landor’s work from the 1823 Guide forward. The passage, as loosely translated by John Talbot, reads: “You really ought
to visit the fields of Tivoli, and the lake of Albunea, with its leafy floating islands.”
The lake of Albunea is the Lago Albano.

Latin: a mystery or freak of nature.