OBSERVATIONS BY BOUSStNGAULT. 115 



variatioti in the annual average quantity of rain. But, so far as they 

 go, they show that at Marmato the mass of running water had 

 diminished, in spite of the larger quantity of rain which fell. It is 

 therefore prohable that local clearings of forest land, even of very 

 moderate extent, cause springs and rivulets to shrink, and even to 

 disappear, without the effect being ascribable to any diminution in 

 the amount of rain that falls." 



These observations are advanced by Boussingualt in connection 

 with the statement that, — " In many localities it has been thought 

 that, within a certain number of years, a sensible diminution has been 

 perceived in the volume of water of streams utilized as a motive- 

 power ; at other points, there are grounds for beUeving that rivers 

 have become shallower, and the increasing breadth of the belt of 

 pebbles along their banks seems to prove the loss of a part of their 

 water ; and, finally, abundant springs have almost dried up. These 

 observations have been principally made in valleys bounded by high 

 mountains, and it has been noticed that this diminution of the waters 

 has immediately followed the epoch when the inhabitants have begun 

 to destroy, unsparingly, the woods which were spread over the face of 

 the land. 



" And here lies the practical point of the question ; for if it is once 

 estabhshed that clearing diminishes the volume of streams, it is less 

 important to know to what special cause this effect is due." 



In a report by Dr Hough, President of the United States Associa- 

 tion for the Advancement of Science, in 1871, are references to 

 climatic conditions there, attributed to the destructions of forest-s ; 

 and, in this connection, referring to the painful accounts which the 

 journals were then giving of the distress in India from famine, ho 

 says, — " From a careful study of this subject, with such data as are 

 accessible in late reports, we cannot doubt that this calamity is 

 largely due to the fact that the forests have within recent years been 

 swept off, by demands for railroad and other uses, much more rapidly 

 than formerly, and that the exposure to winds and sun, thus 

 occasioned, may have largely contributed to these painful results." 



Mr Marsh, in a foot-note supplying indications of what may be 

 called secular desiccation, in regard to which he had said, " After a 

 district of country has been completely or even partially cleared of its 

 forest growth and brought under cultivation, the drying of the soil 

 under favourable circumstances, goes on for generations, perhaps for 



