'The atmospheric theory is as old as Homer. Its laureate is
Montesquieu. The more northerly you go, he said, the sterner the man
grows. You must scorch a Muscovite to make him feel. Gray was a
convert. One of the prose hints for his noble fragment of a didactic
poem runs thus: "It is the proper work of education and government
united, to redress the faults that arise from the soil and air."
Berkeley entertained the same feeling. Writing to Pope from Leghorn,
and alluding to some half-formed design he had heard him mention of
visiting Italy, he continues: "What might we not expect from a muse
that sings so well in the bleak climate of England, if she felt the
same warm sun, and breathed the same air with Virgil and Horace?"

'When Dyer attributes the faults of his _Fleece_ to the Lincolnshire
fens, he only awakes a smile. Keats wrote his Ode to a Nightingale--a
poem full of the sweet south--at the foot of Highgate Hill. But we
have the remark of Dryden--probably the result of his own
experience--that a cloudy day is able to alter the thoughts of a man;
and, generally, the air we breathe, and the objects we see, have a
secret influence upon our imagination. Burke was certain that Milton
composed _Il Penseroso_ in the long, resounding aisle of a mouldering
cloister, or ivied abbey. He beheld its solemn gloom in the verse. The
fine nerves of the mind are braced, and the strings of the harp are
tuned, by different kinds of temperature. "I think," Warburton
remarked to Hurd, "you have often heard me say, that my delicious
season is the autumn--the season which gives most life and vigour to
my intellectual faculties. The light mists, or, as Milton calls them,
the steams that rise from the fields in one of these mornings, give
the same relief to the views that the blue of the plum gives to the
appetite."