( 680 ) 
In the accompanying table I tried to make clear the alternations 
of dry and wet periods of rainfall for some stations in the Netherlands, 
by the decadal sums, progressing from year to year, according to 
the method made use of by Brickner. In the first place we take 
Maestricht having the most continental situation of all the meteoro- 
logical stations in the Netherlands with many years’ determinations of 
rainfall, and being nearest to the basin area of the lower Rhine in 
Germany (Cleves, Bonn, Triers, Nancy), then Utrecht as intermediate 
between that station and Helder and Leiduin, which most of all the old 
stations may approach to the conditions obtaining in the dunes. The 
fifty-years’ average rainfall of the three first-named Dutch stations 
is computed over 1859 till 1908, the average of Leiduin over 49 years 
only, beginning with 1860, the averages for Germany are over the 
years 1851 till 1900. The double years indicate the middle of each 
decade. 
Now, what we observe is a close agreement and conformity to 
the rule of Brtckner, generally, till 1882. In the last (dry) 
period, however, Helder and, in a still higher degree, Utrecht 
show important deviations. Maestricht, on the contrary, agrees very 
well and Leiduin tolerably with Germany and at the same time 
with by far the majority of all the countries of the world. Also after 
1896, till 1900, also in the basin of the lower Rhine in Germany, 
just as at Maestricht, the rainfall remains considerably below the fifty- 
years average. About the beginning of the twentieth century the expected 
change took place every where. In the lower basin of the Rhine in 
Germany the rainfall in the years 1896 till 1900 exceeds the fifty- 
years’ average by 4, 8, 10, 6 and 4°/,, and in the latest lustrum 
the rainfall at Maestricht was nearly 10°/, above the average, but 
not so at the three remaining stations, where deficits of 5, 11 and 
12 °/, were observed, the wet period evidently not yet having com- 
menced. On account however of the agreement with regular regions, 
during so long a time, as well as of the circumstance, that anticipation 
or retardation of an epoch is accustomed to be regained in the next 
period, the probability must not be called small, that for the whole 
of the Netherlands an epoch of increased rainfall and of higher 
ground-water levels is at hand, and that especially in the dunes too 
the ground-water will soon be rising. | 
Undoubtedly not only the annual rainfall, but also the evaporation is of 
consequence for that rising. But we know that evaporation is relatively 
small in periods of much rain and that, generally, the ground-water 
rises and falls with the amount of rainfall. 
Variations in the rainfall are very strongly indicated by the height 
