xxiv
CLIMATE.
while the open sea is agitated by a brisk tempest. Most of the towns
and villages on the coast lie in crescent - shaped bays, opening
towards the S., while on the landward side they are protected by
an amphitheatre of hills. These hills are exposed to the full force
of the sun's rays, and the limestone of which they are composed
absorbs an immense amount of heat. It is therefore not to be
wondered at that these hothouses of the Riviera show a higher tem¬
perature in winter than many places much farther to the S. Thus,
while the mean temperature of Rome in the three coldest months is
46° Fahr., that of the Riviera is 48-50°.
It would, however, be a mistake to suppose that this strip of
coast is entirely free from wind. The rapid heating and cooling of
the strand produces numerous light breezes, while the rarefaction
of the masses of air by the strength of the sun gives rise to strong
currents rushing in from the E. and W. to supply the vacuum. The
most notorious of these coast-winds is the Mistral, which is at its
worst at Avignon (p. 12) and other places in the Rhone Valley,
where it may be said without exaggeration to blow on one of every
two days. As a rule this wind lasts for a period of 3-17 days at a
time, rising at about 10 a.m. and subsiding at sunset; and each
such period is generally followed by an interval of calm and fine
weather. As the Mistral sweeps the coast from W. to E. it gradu¬
ally loses its strength, so that at SanRemo, for instance, it is much
less violent than at Cannes or Hyeres. The N.E. wind on the con¬
trary is much stronger in Alassio and San Remo than on the coast
of Provence. The Scirocco as known on the Ligurian coast is by no
means the dry and parching wind experienced in Sicily and even
at Rome; passing as it does over immense tracts of sea it is gener¬
ally charged with moisture and is often followed by rain.
The prevalent belief that the Riviera has a moist climate, on
account of its proximity to the sea, is natural but erroneous. The
atmosphere, on the contrary, is rather dry, especially in the W.
half of it, while the humidity rapidly increases as we approach
the Riviera di Levante. The same holds good of the rainfall.
While Nice has 36 rainy days between November and April Men-
tone has 44, Nervi 54, and Pisa 63. The average number of rainy
days during the three winter months in the Riviera is 16. Snow
is rarely seen; it falls perhaps once or twice in the course of the
winter, but generally lies only for a few hours, while many years
pass without the appearance of a single snow-flake. Fogs are very
rare on the Ligurian coast; but a heavy dew-fall in the evening is
the rule. In comparison with the Cisalpine districts, the Riviera
enjoys a very high proportion of bright, sunny weather.
The mildness of the climate of the Riviera requires, perhaps, no
better proof than its rich southern vegetation. The Olive, which is
already found in the neighbourhood of the N. Italian lakes, here
attains great luxuriance, while the Eucalyptus globulus (which
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