35 



the Ottawa Dead Letter Office, and from that bourne few travellers return. I therefore 

 give it as it appeared in the newspaper : — 



ij^OEBST AND RAINFALL. 



The following abridgment of the paper on this subject, read by Mr. P. H. Bryce, 

 M.A., of the Ontario School of Agriculture, before the Canadian Institute, wiU be found 

 interesting : — ■. 



" That there is an estimate relation between forests and rainfall, and that the destruc- 

 tion of forests produces aridity and finally sterility, seems to have been long understood, 

 the Greeks recognizing the truth of it by considering it unpardonable to cut down the 

 olive trees in an enemy's country. The opinion of Bernard Palissey and the prediction of 

 Mirabeau, as regarded the destruction of forests in France were sustained, and in other 

 countries the voice of warning has been heard against this evil. 



" The remark of Governor Hant, of Denver, Colorado, " I am convinced that farming 

 in Colorado resolves itself into a question of water, and its judicious application," the 

 reader held to be largely true concerning various branches of farming in Ontario. In 

 Canada, however, it was more a question of regulating the supply, or of obtaining it at 

 the proper periods. That the Canadian climate has undergone great changes in the last 

 forty years is looked upon largely as an inexplicable fact, while the scientist regards it as 

 an efieot dependant on physical causes known or hidden. 



"The whole area of Ontario is 121,260 square miles, while that of the lakes about it 

 is 100,000 square miles j a large portion of the Province must, therefore, be affected by 

 this large body of water. In the autumn, when the earth's position causes a declination 

 of the sun's rays, the surface of the treeless land becomes very rapidly cooled by radia- 

 tion, and with this cooling vegetable growth largely ceases. The lake waters, however, 

 which during the summer have been slowly storing up heat, do not radiate it thus rapidly, 

 while experiment shows that in September the temperature of the water, at least in Lake 

 Ontario, is higher than that of the land. In November, 1837, the water according to 

 Professor Dewey, averaged forty-six and the land thirty-six degrees. The land begins to 

 feel the influence of the growing sun by January, when the water has radiated most of its 

 heat. During the whole of this period, however, the land has had sweeping over it, 

 currents of air with their temperature elevated by contact with the warmer surface of the 

 waters in the regions lying to the north and north-west. These, carrying moisture, come 

 in contact with the cold land, and mists and rains are precipitated. 



" Not only does the cold land cause precipitation of this moisture, but the much higher 

 level of much of the land over that of the lakes increases the cold at about the rate of one 

 degree for every 430 feet, and, therefore, increases precipitation. Add to these causes 

 the influence of the north-east winds, cooled by passing over great extents of land surface, 

 and some idea is had of the principal causes which conduce to the great snow falls of the 

 central plateaux of this Province, whUe the lower and more southern countries obtain the 

 same amounts of moisture largely as rain. Another set of phenomena mark the progress 

 of spring, the advent of which is marked by the great prevalence of northerly winds, of 

 which, on the whole, we seem to have more now than thirty years ago. The reasons for 

 these northerly winds seems evident. By the 20th of March the sun's rays are beating 

 powerfully upon the earth for twelve hours per diem, rapidly elevating its temperature. 

 The atmosphere over the land, becoming heated, rises, and its place is supplied by cold 

 winds coming in from the lakes, especially from the ice-cold waters and ice-fields of 

 Georgian Bay and Lake Huron. Conditions the opposite of those of winter now exist. 

 Instead of the moisture of the winds from the lakes becoming condensed as the winds 

 blow over the land, the wind becomes drier, because warmer, and only when a cold north- 

 east current meets these moist currents from the lakes will the moisture be precipitated. 

 In the summer months we find long days, and also the perpendicular rays of the sun, 

 elevating to an enormous extent the temperature of the treeless surface, while from the 

 surrounding lakes purrents of cooler air are continually rushing in to supply the place of 

 the ascending heated column. These cooler lake breezes, while keeping our climate more 



