186 EFPECTS or rOBEST YECtZTAT:0>' Oy CLIlIi.TE. 



the rivers, in the Xevr World owe their origin to the forests of 

 America, aud their destruction might dry np many a rivulet, and 

 thus again convert the luxuriant valley into an arid and sterile 

 waste ; carried further, the principle extends to the great features 

 of the globe. What the glaciers eftect among the higher regions 

 of the Alps, the Vinus cemhra, and Larix communis accomplish at 

 lower elevations, and many a moimtain rivulet owes its existence 

 to their influence. It rain.s often in the woodlands when it rain.s 

 nowhere else, and it is thus that trees and woods modify the 

 hygromctric character of a country : and I doubt not but. by a 

 Judicious disposal of trees of particular kinds, many lands now 

 parched up with drought, as for example, in some of the Lee- 

 ward Islands, might be reclaimed from that sterility to which they 

 are unhappily doomed." (M. X. H., vol. IT., p. 32-3i.) 



I shall, before I conclude, put in evidence what will prove the 

 truth of this sug2:estion from one of the group of islands men- 

 tioned. 



But before I proceed. I wish to mention a statement made to 

 me by more than one reKable informant respecting the power of 

 Australian trees in time of di'ought to produce water from their 

 roots. I vras travelling with a friend in the month of January 

 of the ]3resent year in the valley of Bylong in the county' of 

 Phillip, during the height of the di'ought. Among other circum- 

 stances brought to our notice was tliis — that water had made its 

 appearance by springing up in several places where none had ever 

 before been noticed, and the explanation given was that such 

 water came fi'om the roots of the gum trees. This opinion I 

 heard uttered by several close observers, and I think it possible, 

 when one considers the natui'e of the roots of these trees, and 

 the effect of di'0U2:ht in coiitracting the wood, in checking the 

 ascending sap and squeezing it out. I name this moi*e to elicit 

 observation and explanation from others than to lay it down as a 

 fact sufficiently established : but I am inclined to believe there 

 may be more in it than is *' dreamed of in our philosophy " of 

 droughts ; and I know no other solution for the fact, if it be gueh. 

 than the one I have suggested. 



Professor Dobereiner. of Jena, mentions in the BiUiothtque 

 TTniverselle that it has been noticed that on the hio^h mountains 

 of South America the trees continually transpired a quantity of 

 water, even in the driest weather, the water falling sometimes as 

 rain. This is a parallel case to that cited before from the island 

 of Hierro. 



Certain trees have been tapped for a supply of water, and the 

 roots haAc often been found to discliarge it sufficiently to assuage 

 human thirst. These have been called the '*' Traveller's Tree.'' 



Now, I believe it has been ascertained that the fibres of wood 

 in trees are composed chiefly of carbon, oxygen, and hydrogen — 



