In Upper Canada the climate does not present such extremes of heat and cold as in the Lower Province. In the Newcastle District, between latitude 44 deg. and 45 deg., the winter is little more severe than in England, and the warmth of summer is tempered by a cool and refreshing southwest breeze, which blows throughout the day from over the waters of the great lakes. In spring and autumn the southwest wind brings with it frequent rains; the northwest wind prevails in winter, and is dry, cold, and elastic; the south-eastern breezes are generally accompanied by thaw and rain: from the west, south, or north, the wind rarely blows. The most sudden changes of weather consequent upon varying winds are observed from the northwest, when the air becomes pure and cool; thunder storms generally clear away with this wind: the heaviest falls of snow, and the most continued rains, come with the eastern breezes. The great lakes are never frozen in their centers, but a strong border of thick ice extends for some distance from the shore: in severe weather, a beautiful evaporation in various fantastic shapes ascends from the vast surfaces of these inland seas, forming cloudy columns and pyramids to a great height in the air: this is caused by the water being of a higher temperature than the atmosphere above. The chain of shallow lakes from Lake Simco toward the midland district are rarely frozen over more than an inch in thickness till about Christmas, and are free from ice again by the end of March. The earth in Upper Canada is seldom froze more than twelve or eighteen inches deep, and the general covering of the snow is about a foot and a half in thickness. In Canada the Indian summer is perhaps the most delightful period of the year. During most of November the weather is mild and serene; a soft, dry haze pervades the air, thickening toward the horizon; in the evenings the sun sets in a rich crimson flush, and the temperature is mild and genial: the birds avail themselves of the Indian summer for their migration. A phenomenon called the "tertian intervals" has excited much interest, and is still unexplained: at the end of the third day the greatest intensity of frost is always remittent, and succeeded by several days of mild weather. The climate is so dry that metals rarely are rusted by exposure to the air. This absence of humidity prevents the extremes of heat and cold from being so powerful here in their effect upon the sensations of the human frame as in other countries.