TRANSACTIONS OF SECTION E. 317 



destroyed by settlers and accidental fires, would exhibit the 

 main features of the aimual rainfall. In countries that have 

 been long settled and cultivated it is impossible to determine 

 what were the areas of virgin forest. It is only in a country 

 such as ours, just placed in the hands of civilised man, and 

 where the aboriginal inhabitants have not been given to felling 

 and clearing on an extensive scale, that such an inquiry 

 becomes possible ; and, as to determining or helping to deter- 

 mine what are or have been the areas of greatest precipitation, 

 it may surely be considered, next to exact meteorological 

 statistics, as of paramount importance. 



Certainly different kinds of trees require different degrees 

 and amounts of moisture, as of heat, light, and elevation, to 

 develope them. Some, indeed, seem specially adapted by 

 nature for dry climates and positions : they have hairs cover- 

 ing their leaves, which thus attract a larger proportion of dew, 

 or their leaves are needlelike, or set on edge, so that during a 

 drought the sun has less effect on them. It would almost 

 appear as if the Eucalyptus when grown in a moister climate 

 than that in which it is indigenous alters its habit of growth. 

 In New Zealand here, its leaves grow less edgewise, more open 

 and flat to the sky, as if they felt they could safely expose 

 themselves to a less powerful sun in a climate where moisture 

 is happily so plentiful as to temper materially his ardent rays. 

 But all these are quite exceptional characteristics of particular 

 species, and are instances of modification of form to protect 

 life and accommodate it to its environment. 



It would be quite possible to bring out the truth of the 

 proposition submitted as to the relationship between rainfall 

 and forest by a survey of the surface of the earth generally. 

 Some instances could be given which pointedly confirm the 

 theory: e.g., the northern and eastern portions of the Island 

 of Madagascar, where the climate is moist, are clothed with 

 magnificent forest, whereas elsewhere in the island the vege- 

 tation is remarkably scanty, there being only a narrow arbore- 

 ous belt along the shores. But it is very difficult to conduct 

 the inquiry as to the earth generally with precision, because 

 there are large areas in the world over which the extent of 

 woodland is very imperfectly mapped out, or, indeed, known ; 

 and unfortunately, too, these are precisely the regions where 

 the rainfall is conjectured rather than measured. Moreover, 

 where the forest-area and the mean annual average of rain are 

 well known and duly recorded, there the condition precedent 

 that the forest be indigenous and virgin does not obtain ; for 

 the countries referred to have been so long settled that few 

 spots, if any, are left in true primitive wildness. Similar un- 

 certainty, indeed, may exist as to the reading of such cases as 

 Makatu Island, in the Fijis, where the windward and pre- 



