and Climate in Victoria. 5 



air over forests. Air nearly saturated with moisture, drifting 

 over the heated surface of the open country and meeting 

 with this cooler stratum, not unfrequently becomes con- 

 verted into a falling mist or actual rain. In fact, the diminu- 

 tion of temperature over the forest has the same effect upon 

 moisture-laden winds as a range of hills — namely, to 

 encourage precipitation. 



It is highly probable that forests have another influ- 

 ence on the atmosphere, which, although not yet 

 thoroughly recognised, and perhaps not generally 

 admitted, may nevertheless prove to be most power- 

 ful. I refer to electric influence; and from the results of 

 a few observations and experiments I have made at 

 different times on atmospheric electricity in forests, and some 

 interesting phenomena I have witnessed, I feel certain that 

 what may be called electric exchange, or the balancing of 

 the electric tension of the lower strata of the atmosphere 

 over forests, plays an important part in condensation and 

 precipitation. In making an electric contour over large 

 trees in forests, I have always found the equipotential line 

 to come closer to the tops of trees than any other objects ; 

 and this may possibly account in part for the well-known 

 rapid condensation by tall trees of the drifting mist in hill 

 forests, by which an immense amount of water, not counted 

 in our rainfall, is annually precipitated. 



Some months ago when on Mount Maceclon, about 3000 

 feet above the sea, in company with our Vice-President, 

 Mr. Foord, we watched the gradual condensation of air-borne 

 moisture into mist-clouds. As it was driven up the southern 

 slopes of the mountain, our attention was attracted by 

 some peculiar rifts in the mist-clouds, which occurred as 

 they passed over an isolated dead tree near the summit of 

 the mountain. They appeared as almost vertical dark 

 streamers radiating from the topmost dead limbs of the tree, 

 and waved about much in the same way as one sees the 

 brush discharge from an electric machine, or the secondary 

 discharge of an induction coil. We were both impressed 

 with the idea that the phenomenon was electrical. The 

 part electric tension plays over the surface of forests, pre- 

 sents, I think, a new field for meteorological enquiry. 



From these facts, meagre as they are, I think it will be 

 conceded that our forests play a most important part in 

 our climate ; that without them, while our rainfall might 



