OF THE RIVER SAINT LAWRENCE. 



273 



perature ; and at twenty-two stations at which the mean annual range is below that of the 

 whole district, all but one are in the vicinity of lakes or rivers. 



As compared with Europe, easterly winds bear the same relation to the rains that 

 westerly winds do on our side ; for in each case the humid air from the Atlantic is brought 

 over the continent, where, upon cooling, it must precipitate its moisture. In the Northern 

 United States and Canada, northeasterly storms are proverbial for their inclemency ; 

 whereas northwesterly winds, bringing air from which the moisture has been previously 

 condensed, have a chilling, but not a rainy character. 



A statement of the quantity of rain, as observed at a variety of stations, is given in the 

 Appendix, No. 9 ; and to add to the value of those observations taken in Canada, the 

 result of observations made in the State of New York is also »ivcn. 



It will also be seen that the last rain in the State of New York appears to fall in the 

 valley of the St. Lawrence, and the western portions of that State ; and, therefore, the 

 region of the great lakes receive a rain fall below the general average. 



The rainy season is greatest in summer and autumn during the prevalence of ocean 

 winds, and, coincidently, it is least in the spring and winter, when the land winds prevail. 

 The least depth of rain, including snow (eight inches of which are assumed to equal one 

 inch of rain), falls in February, the greatest in June ; the quantity falling, in August 

 being nearly equal to the annual monthly mean. From May to November it is greater, 

 and during the remainder of the year it is less than the general average. 



The relative forwardness of the seasons may be best obtained by referring to a state- 

 ment of the duration of closed navigation at various points, given at page 265, under the 

 article "Ice." 



With respect to the temperature of the waters of the valley of the St. Lawrence, the 

 writer is not aware of any other continued observations than those which have been made 

 in the Iliver St. Lawrence, at Montreal. 



The observations recorded by Mr. Hodges, in his elaborate description of the Victoria 

 Bridge, and its works, contain some interesting matter relating to that feature of the St. 

 Lawrence. 



In order to render the subject more complete, the writer has given below the result of 

 one year's observations on the mean temperature of the water, and the mean temperature 

 of the air, taken at two stations, at 9 a.m., noon, and 3 and 6 p.m., for the year 1861, near 

 to the city of Montreal. These results show that the mean temperature of the year was 

 45.03°; that the mean of the air, during November, December, January, February, and 

 March, 151 days, was 24.20°; that the maximum was 47.50°, and the range 76°; and 

 that the number of days at and below zero was 16 ; at and below 32°, 113 ; and at and 

 below 24.20°, the mean, 75. That in the next period, — April, May, and October, — 92 

 vor,. xiii. — 85 



