43 



students of physical science should be incited to further research into the cause of these 

 intimately connected phenomena, and then to devise measures to avert the impending 

 calamity, in so far as it may be within the scope of man's power to do so." 



The author adds : — " I have given myself also to an attempt to a solution of this 

 difficult problem, and I give the results of my researches in this study in the two follow- 

 ing chapters, in the hope that distinguished collaborateurs in the same calling, and men 

 of scientific attainments may prosecute further the researches I have been privileged to 

 commence, and that the results of their study may bring great good to the generations 

 yet unborn. 



The chapter which follows is occupied with a discussion of the cause or occasion of a 

 diminution having taken place in the quantity of water flowing in streams and rivers, 

 which he thus concludes : — 



" When we fully realise what is implied in the opinions expressed by men of science, 

 and practical men expert in such matters, in various countries, and in very diflTerent parts 

 of the world, after long experience, observation and research, we find that forests efiect 

 to a very great extent the quantities of water coming from springs and flowing in rivers ; 

 that they affect the climate ; and that they have a good effect upon the fertility of the 

 lands in which they exist ; and that thus : — 



" 1. The deposit of rain from the atmosphere is greatly increased by the amount of 

 woods in a district, inasmuch as mists and clouds passing along the surface, striking 

 upon the forests, have the moisture of which they are formed condensed and precipitated 

 as rain. Further the temperature within the woods is cooler by day, and, on the con- 

 trary, warmer by night than it is in the open fields and meadows ; and by reason of this, 

 there is a continual circulation of air in the vicinity of forests whereby mists and clouds 

 are precipitated and led to discharge themselves of their contents. This happens not 

 through the forests in and for themselves, nor as a consequence of the forests of them- 

 selves, but through the difference between the forests and the open fields ; and on this 

 depends the abundance of the rain. It is also very manifest that the forests exercise an 

 attractive influence upon the clouds, by their attracting from them electricity with which 

 they are charged, and with this the water of which they are composed, increasing 

 thereby the rainfall. It is also an ascertained fact that a great part of the water precipi- 

 tated as rain remains on the leaves of the trees, one part of which falls to the ground, 

 but another portion of which evaporates into the atmosphere, and is again precipitated as 

 fog, mist, dew, or rain, — whence it comes to pass that rain water is kept longer within 

 forest lands, and may be precipitated oftener than once, whereby the rainfall is 

 increased. 



"2. Through the abundance of forests will the copiousness of the subterranean drainage 

 flow, and springs be increased, while the rainwater retained by the foliage of the forest 

 trees, falling slowly to the earth, is kept by the spongy character of the ground in woods, 

 from flowing quickly away, and is in part absorbed, or is left to permeate the mineral 

 strata, which is considerably facilitated by the numerous spreading roots of the trees 

 penetrating cracks, fisures, and canals in the superficial ground, by which means the 

 rainwater reaches a greater depth, and this in a much greater quantity in forest ground 

 than in the open field. Further, by numerous experiments, it has been established that 

 the evaporation of the humidity in the open country is at least from four or five times as 

 great as it is in woodlands ; from all which it appears that the moisture absorbed in forests 

 is not so readily evaporated, but it is retained and directed to the feeding of drainages, 

 springs, and brooklets. 



" 3. If forests be uprooted, more especially in mountainous regions, or even in 

 somewhat hilly country, the raindrops, falling upon the exposed ground with some force, 

 tear it up, and then, flowing down the declivity with considerable rapidity carry with 

 them earth and stones towards the brooks, and streams, and rivers, by which these water 

 courses are suddenly filled up, and experience much higher and more devasting overflow- 



