TREATISE BY HERR WEX. l89 



that since the clearing away of many forests, more especially in the 

 mountains, deluges of rain and rain-spouts occur more frequently ; 

 further, while the rain-water, in lands devoid of trees, sinks less into 

 the soil, it at the same time more speedily reaches the brooks 

 and streams and rivers, and fills and overflows these water-courses ; 

 and finally, the body of water, now tearing along with rapidity, cuts 

 up the mountain sides cleared of forests, and fills up the beds of the 

 brooks and streams and rivers with earth and sand and rubbish, and 

 so raises the bed of the river — whence a higher level is reached by the 

 water-surface. 



" The correctness of this allegation is being attested, in a way 

 which it is saddening to contemplate, by the ever more frequently 

 recurring inundations in Italy, in the south of France, in Hungary, 

 in Bohemia, and in many other lands. 



" The aforementioned phenomena of high floods led a disthiguished 

 meteorologist to express to me the conjecture that the great increase 

 of the body of water passing along our water-courses, in high floods, 

 may be about equal to the diminution observable in the low and 

 mean levels. 



" This conjecture, however, is not in accordance with the facts of 

 the case, because, as I have already shown, in the case of the Rhine 

 and of the Elbe, the annual delivery is approximately represented by 

 the mean water-levels, which, even in all these five rivers named, is 

 on the decrease. But the incorrectness of the conjecture is more 

 particularly manifested by the tabulated observations by the pegel at 

 Orsova, in as much as, from the geographical position of the very 

 extensive basin drained by the Danube, it frequently happens that 

 the high floods of several of the large afiluents coincide in time with 

 that of low water level in several other important accessories of the 

 river, and yet there is not an equivalent compensation for the lesser 

 supply coming from the one class of affluents, in the greater supply 

 coming from the other, in as much as, even at Orsova, the average 

 of the floods of the mean and of the lowest levels have fallen still 

 more than have these in the four other rivers named. 



"But even if, in accordance with this conjecture, in particular years 

 with repeated extraordinary high floods, some such equalisation of 

 the increased and the diminished delivery of a river should occur, 

 this would supply but little consolation for man, as the great evils 

 consequent on the diminution of the delivery of water at the lowest 

 and the mean levels are not obviated by the more frequent occurrence 

 of the greater delivery during high floods, but are being more than 



