Not only do mountains thus determine the absolute quantity of rain, they also affect the number of rainy days in a year. The occurrence of a rainy season depends on the amount of moisture existing in the air; and hence its frequency is greater at the Atlantic sea-board than in the interior, where the wind arrives in a drier state, much of its moisture having been precipitated by the mountains forcing it to a great elevation. Thus, on the eastern coast of Ireland it rains 208 days in a year; in England, about 150; at Kazan, 90; and in Siberia only 60 days.
and of snowy days.
When the atmospheric temperature is sufficiently low, the condensed water descends under the form of snow. In general, the annual depth of snow and the number of snowy days increase toward the north. In Rome the snowy days are 1½; in Venice, 5½; in Paris, 12; in St. Petersburgh, 171. Whatever causes interfere with the distribution of heat must influence the precipitation of snow; among such are the Gulf Stream and local altitude. Hence, on the coast of Portugal, snow is of infrequent occurrence; in Lisbon it never snowed from 1806 to 1811.
Such facts teach us how many meteorological contrasts Europe presents, how many climates it contains. Necessarily it is full of modified men.
Vibrations of the isothermal lines.
If we examine the maps of monthly isothermals, we observe how strikingly those lines change, becoming convex to the north as summer approaches, and concave as winter. They by no means observe a parallelism to the mean, but change their flexures, assuming new sinuosities. In their absolute transfer they move with a variable velocity, and through spaces far from insignificant. The line of 50° F., which in January passes through Lisbon and the south of the Morea, in July has travelled to the north shore of Lapland, and incloses the White Sea. As in some grand musical instrument, the strings of which vibrate, the isothermal lines of Europe and Asia beat to and fro, but it takes a year for them to accomplish one pulsation.
Europe is full of meteorological contrasts, and therefore of modified men.
All over the world physical circumstances control the human race. They make the Australian a savage; incapacitate the negro, who can never invent an alphabet or an arithmetic, and whose theology never passes beyond the stage of sorcery. They cause the Tartars to delight in a diet of milk, and the American Indian to abominate it. They make the dwarfish races of Europe instinctive miners and metallurgists. An artificial control over temperature by dwellings, warm for the winter and cool for the summer; variations of clothing to suit the season of the year, and especially the management of fire, have enabled man to maintain himself in all climates. The invention of artificial light has extended the available term of his life; by giving the night to his use, it has, by the social intercourse it encourages, polished his manners and refined his tastes, perhaps as much as any thing else has aided in his intellectual progress. Indeed, these are among the primary conditions that have occasioned his civilization. Variety of natural conditions gives rise to different national types, artificial inventions occasion renewed modifications. Where there are many climates there will be many forms of men. Herein, as we shall in due season discover, lies the explanation of the energy of European life, and the development of its civilization.
Would any one deny the influence of rainy days on our industrial habits and on our mental condition even in a civilized state? With how much more force, then, must such meteorological incidents have acted on the ill-protected, ill-clad, and ill-housed barbarian! Would any one deny the increasing difficulty with which life is maintained as we pass from the southern peninsulas to the more rigorous climates of the north? There is a relationship between the mean annual heat of a locality and the instincts of its inhabitants for food. The Sicilian is satisfied with a light farinaceous repast and a few fruits; the Norwegian requires a strong diet of flesh; to the Laplander it is none the less acceptable if grease of the bear, or train oil, or the blubber of whales be added. Meteorology to no little extent influences the morals; the instinctive propensity to drunkenness is a function of the latitude. Food, houses, clothing, bear a certain relation to the isothermal lines.
But, through artificial inventions, it tends to homogeneousness in modern times.