The theory by which Dr. Brewster seeks to account for the peculiarities of the American climate is the following: "He supposes that the poles of the globe and the isothermal poles are by no means coincident, and that, on the contrary, there exist two different points, within a few degrees of the poles, where the cold is greatest in both hemispheres. These points are believed by Dr. Brewster to be situated about the eightieth parallel of latitude, and in the meridians of 95° east and 100° west longitude. The meridians of these isothermal poles[223] he considers as lying nearly at right angles to the parallels of what might be called the meteorological latitudes, which, according to his theory, appear to have an obliquity of direction as regards the equator something like the zodiac. Thus the cold circle of latitude that passes through Siberia would be the same that traverses the frigid atmosphere of Canada. This theory would go some length toward explaining the causes of the gradual decrease of the severity of cold in the south of Europe, and lead us to the conclusion that eventually the cold meridian of Canada may work its way westward, and leave that part of America to an enjoyment of the same temperature as those European countries situated in corresponding latitudes. That the temperature of the air has been modified by agricultural operations can not be denied, but that these operations should of themselves be capable of producing the changes known to have taken place in the course of ages in Europe, where formerly the Tiber used to be often frozen, and snow was by no means uncommon at Rome;[224] when the Euxine Sea, the Rhone, and the Rhine, were almost every year covered with ice, of sufficient thickness to bear considerable burdens, it is scarcely possible rationally to admit; and, indeed, the meteorological observations, as far as they go in Canada, serve rather to disprove than to establish the fact."--Bouchette, vol. i., p. 335. "The earliest record of the climate of Canada is that contained in the 'Fastes Chronologiques,' and refers to the period of Cartier's second voyage. On the 15th of November, 1535, Old Style, the vessels in the River St. Charles were surrounded by ice, and the Indians informed Cartier that the whole river was frozen over as far as Montreal. On the 22d of February, 1536, the River St. Lawrence became navigable for canoes opposite to Quebec, but the ice remained firm in the St. Croix harbor. On the 5th of April his vessels were disengaged from the ice. To obtain the modern dates, it will be necessary to add eleven days to each period.