He hath no morn nor night, but all is dark

Within—and what seest thou? A dubious spark!

LXXII.

But I'm relapsing into Metaphysics,

That labyrinth, whose clue is of the same

Construction as your cures for hectic phthisics,

Those bright moths fluttering round a dying flame:

And this reflection brings me to plain Physics,

And to the beauties of a foreign dame,

Compared with those of our pure pearls of price,