District between Portage lake and the Montreal river-Continued. 34 21 Northeast quarter.... Ridge of trap.. 361 34 20 Southwest quarter.. Stream, 10 feet above small lake.. 126 34 30 Southeast quarter.......... 35 36 Northwest quarter.. Summit of ridge near southwest corner of southeast quarter 35 36 Corner of sections 25, 26, 35, 36. 99 NOTE. For the information of those not familiar with the system of government surveys, it may be stated that the public domain is surveyed into town This system, which is an admirable one, was first suggested by Hutchens, who, before the Revolution, belonged to the royal engineers, and subsequently This system is executed with a chain and compass, which, under all the circumstances, is the best which could be devised for this country, where the forests are so dense as to render it impossible to make use of those natural monuments which are essential to connect triangulations, Burt's solar compass is an admirable invention, and ought to be substituted for that in ordinary use in all the public surveys, 403 263 234 188 263 175 276 CHAPTER II. CLIMATE. Objects embraced.-Meteorology.-Effects of the lakes in equalizing the temperature.-Meteorological registers, at various stations.-Mean annual temperature, and that of summer and winter.-Amount of rain.Course of the winds.-Comparison of the climate in equal latitudes in Europe.--Character of the vegetation.-Range of the cerealia.-Oscillations in the lakes.-The cause.-Periodic rise-Temperature and transparency of the water of Lake Superior.-Evaporation.—Mirage.Variation of refraction.-Frosts.-Thunder-storms.-Auroras. Meteorology.-In treating of the climate of this region, we shall use that term in its most extended sense, as comprehending, according to Humboldt, all the changes in the atmosphere which seriously affect our organs-as temperature, humidity, variations in the barometrical pressure, the calm state of the atmosphere or the action of opposite currents of winds, the amount of electric tension, the purity of the atmosphere or its admixture with more or less noxious gaseous exhalations, and, finally, the degree of ordinary transparency and clearness of the sky, which is not only important with respect to the increased radiation of the earth, the organic development of plants, and the ripening of fuits, but also with reference to its influence on the feelings and mental condition of men. To this great physicist science is indebted for having first suggested a system of lines, called isothermal, isotheral, and isochimenal, connecting those places where the mean summer, winter, and annual temperatures have been ascertained. These lines are by no means parallel, various causes conspiring to produce divergencies-such as altitude above the sea, the geographical configuration of a country, the presence or absence of large bodies of water and of mountain chains, the purity of the sky, and the prevailing direction of the winds. Isothermal lines define the heat and cold of the earth. The line 59° F. traverses the latitude of 43° in western Europe, but descends to latitude 36° in eastern America. The isothermal line of 41° F. passes from latitude 60° in western Europe to latitude 48° in eastern America. The presence of so vast a body of water as is afforded by the American lakes modifies the range of the thermometer, lessening the intensity of the cold in the winter and of the heat in the summer. By the freezing of the water, a great volume of heat is evolved, and the intense cold of the northern winds is somewhat mitigated in sweeping over the open lakes. In the summer, when the sun, often with unobscured lustre, shines for sixteen hours in twenty-four, the intensity of the heat is modified by the breezes which are cooled in their passage over the surface of the lakes, the water of which is always at a low temperature. To show the equalizing effects of the lakes on the climate, we need *Asie Centrale-Tome III. Mean T. Winter. SummerT. Ran 44°.3 20°.5 670.7 -10 44°.8 16°.3 720.0 -23 Thus, during the winter, the mean temperature at the forme higher; but during the summer it is lower, while the annual tem is nearly the same. The former is situated in the proximity bodies of water, which essentially modify the temperature; while ter is in the midst of a vast plain, with no mountain chains to br force of the winds. Weather. [The following tables have been furnished us from the office of the Surgeon General of the United States army, made in pursuance of an admirable regu- Days. |