oe 
514 Are We Drying Up? [September, 
pears to be true, at all events, that exact observations with the 
rain-gauge have not yet anywhere been kept up for a sufficient 
time to enable us to speak with certainty with regard to the 
existence of any secular change in the amount of rain falling at 
any one place. The length of time during which such observa- 
tions have been made is but trifling compared with the dura- 
tion of the historical period, and infinitesimally small when con- 
sidered with reference to even the most recent of the geological 
epochs. 
We have, however, as will be seen; abundant evidence of a 
great change over at least a considerable part of the earth’s sur- 
face, in the amount of water distributed in the lakes or running 
in the rivers, and it can be shown, beyond a doubt, that this 
change has been taking place within a very recent period, speak- 
ing geologically. Some important evidence can also be adduced 
to the effect that this change has been continued in the historical 
epoch, although not yet capable of demonstration by the recorded 
observations of the rain-gauge. . 
ere are two regions especially where the facts already col- 
lected show most clearly, not only a diminution in the amount of 
water existing on the surface, but a most striking one. In Cen- 
tral Asia and in Western North America, the observations of 
numerous observers all point unmistakably in this direction. 
The observations of the Schlagintweits in Thibet and Turkistan 
may first be mentioned. One or two extracts may be given 
from H. von Schlagintweit’s article entitled, “ Investigations om 
Eea T 
SEINE $ 
the Salt Lakes in Western Thibet and Turkistan.” 1 He writes 
as follows: “In all portions of High Asia, south and pe of 
ame 
the main water-shed, there are numerous places where t 
mer existence of mountain lakes may be recognized.” + + + Kp 
Thibet, throughout the entire longitudinal depression between 
the chain of the Himalaya and the main water-shed of the Iara- : 
korum, of the once numerous lakes, but comparatively 
still in existence.” . . . “ So extreme is the dryness in "€ 
Thibet that, in the case of nearly all the lakes still rema 
the evaporation exceeds the supply of water, 
ing condition is at the present time one of gra 
the area covered by water.” There seems to be here, © oa 
bining all the results of the Messrs. Schlagintweits’ observations 
abundant evidence of a marked change of climate in the B 
Cl, II. Band ** 
EEE er ey! Di 
ning, 
` From the Proceedings of the Bavarian Academy of Sciences, 
th. 1. - 
