DIMINUTION OF THE WATER OF RIVERS AND STREAMS. 197 



erable sinking (of 17.35^ aud 34 inches) in the mean of high water and 

 of low water, which he also attributed to changes made in the stream; 

 the deepening of the bed, and the consequent increase in the velocity 

 of the current. 3. The opinion was positively declared that the in 

 recent times more abundant and rapid flowing of the high water would 

 carry away sufficient quantities to account for the decrease in the mean 

 and low water heights. 



The author next shows — 1. From the regular observations of the late 

 Bavarian building-inspector, Grebenau, at Germersheira, of the heights 

 of water of the Rhine from the highest to the lowest, continued during 

 twenty-eight years, which give not only the height, but also the quantity 

 of flowing water, that with the sinking of the mean of the levels there 

 was also a decrease in the amount of water flowing through the rivers. 

 2. That according to the observations of the commission of inspection of 

 the Elbe River, the bed of the stream was deepest when the water-marks 

 were highest, while on the contrary, when the mean middle aud lowest 

 heights had sunken, the bed of the river had been raised by being tilled 

 in with sand, so that the sinking of the water-marks at Madgeburg can- 

 not be attributed to the deepening of the bed of the stream. 3. That 

 the high water cannot compensate for the decrease in the quantity of 

 water at the low and mean heights is proved by Mr. Wex, in the first 

 place by the before-mentioned register of the water-heights at Souder- 

 heim, according to which it is found that the decrease in the entire 

 amount of water is very nearly proi)ortional to that in the water heights; 

 and in the second place by the measurements for thirty-two years of the 

 water-marks of the Danube at Alt Orsova, which show a decrease, not 

 only in the mean and low, but also in the high water recorded, which 

 Mr. Wex correctly attributes to the circumstance that, in the large 

 tributary streams of the Danube, the water is high at different times. 



In reviewing the simple and evident facts given by our author, the 

 commission came to the conclusion that the lowering in the mean and 

 low water heights of the rivers mentioned, observed during the last 

 hundred years, should be attributed to the decrease in the yearly amount 

 of water. 



Mr. Wex now stated that the diminution in the amount of water in 

 these rivers indicated a decrease in the productive jiower of the springs, 

 and further i)roof of this was afforded by the lessening of the water in 

 the brooks, aqueducts, and wells or fountains. 



The commission on this point were in full accord with our author, 

 since they considered amply confirmed the conclusion that with the 

 sinking of the mean of the low-water there was corresi)onding decrease 

 in the springs and in all the water in the neighborhood of the rivers. 



The cause of this decrease in the copiousness of springs may lie — 1. 

 In a diminution, owing to the advance of civilization ; that is, to the 

 uprooting of the forests, in the yearly amount of precipitation. 2. In 

 the increased evaporation from the surface of the earth, also due to the 



