ON SUNSPOTS AND RAINFALL. 



239 



TV. — The Levels of Rivers of Central Europe compared with the Sunspots. 



28. A paper by Herr Gustav Wex, ' On the Decrease of Water in the 

 Wells, Streams, and Rivers,' published in 1873, contains a number of 

 Tables, giving the yearly mean heights (or depths) of water in the Elbe, 

 Rhine, Oder, Vistula, and Danube, for various periods from 1728 to 

 1871. 



Having been favoured with a copy of that important paper, I have 

 compared the annual mean levels of the rivers with the sunspots, in the 

 same manner as the rainfall has been compared, and the results are given 

 in the next five tables. 



From 1799 to 1811 we have (in Austrian feet and inches) the levels 

 of the Rhine, Elbe, and Oder ; from 1811 to 1823 those of the Rhine, 

 Elbe, Oder, and Vistula; from 1824 to 1844 those of the Elbe and 

 Vistula ; and from 1843 to 1867 those of the Elbe, Vistula, and Danube. 



As might have been expected from the results for the rainfall of 

 Europe (Table VII.), the maximum height or level was attained in the 

 mean year of maximum sunspots, and, as a rule, the rivers fluctuated 

 with the sunspots. 



The mean of the mean cycle is 6 ft. 0*9 inches, and for the whole 

 period (1799 to 1867) the mean is 6 ft. l - 8 inches. 



If we omit the years 1799 to 1811, as being in the opinion of some 

 too early, we still get similar results, and likewise similar results for the 

 still later periods 1824-67. 



29. The converse process gives the following results : — 



In the next table we have the Rhine, Elbe, and Oder from 1804 to 

 1816 ; the Rhine, Elbe, Oder, and Vistula from 1817 to 1829 ; the Elbe 

 and Vistula from 1827 to 1839; the Elbe, Vistula, and Danube from 

 1850 to 1862; and the Vistula and Danube from 1861 to 1871. 



The levels in the years of minimum sunspots are placed in the seventh 

 line, because the river variation was found to overlap the sunspot varia- 

 tion to a considerable extent. 



