and Climate in Victoria. 3 



year, show how they are torn from time to time by excessive 

 rain precipitation. This is also the case in some parts of 

 temperate South America, Persia, India, Thibet, and 

 Tartary — and, indeed, it is not unknown to us in Australia. 

 In such places drought is the normal state of affairs, though 

 the annual rainfall is probably greater than in wet England. 

 The simple amount of rainfall does not, therefore, appear to be 

 the only factor which determines a country's humidity or 

 dryness ; while we gather from the instances referred to that 

 the presence of forests must be taken as one of no small 

 importance. 



From carefully conducted experiments it is found that 

 the temperature of trees in forests has a very different march 

 from that of the air, for while the maximum temperature 

 of the air is usually reached about three p.m., that of 

 a forest tree occurs about nine p.m., and while the 

 air is subject to rapid changes, trees are exceedingly 

 slow to alter. The obvious result of this is that the days in 

 a forest are cooler and the nights warmer than in open 

 country. Summer temperature is diminished, and that of 

 winter increased. It is also a well-known fact that forests 

 diminish evaporation from the ground, and act as conser- 

 vators of moisture. 



The greatest extremes of night and day temperature occur 

 in open country, where the unshaded soil readily absorbs 

 the radiant heat of the sun and becomes many degrees 

 hotter than the air. Again rapidly radiating back the heat 

 into space at night (unless it be cloudy), the surface cools 

 down to a temperature far below that of the air, often 

 below freezing point in the middle of summer. Vegetation 

 has a hard straggle for existence ; none but the hardiest 

 species survive, and excessive dryness of the untimbered 

 country (where such country prevails to any extent) un- 

 doubtedly engenders meteorological conditions unfavourable 

 to rain precipitation. It has also been found that the 

 temperature of the sides and slopes of mountains is modified 

 even in a more marked degree than that of level country by 

 the presence of forests. 



So much, then, can be gathered from actual observation 

 and experience in other countries. I now come to our own 

 experience. The greatest annual averages of rain in this 

 colony occur either on or in the vicinity of mountain ranges, 

 and especially on their southern or seaward slopes, and the 



