CAUSES OF DESICCATION EXAMINED. 
577 
retreat of the water. Its present state must therefore be attributed, I think, to a 
gradual drying up of the sea which covered it, till in process of time it became broken 
into a series of lakes, the level of which is determined by the proportion which the 
water poured into them by rivers or falling from the clouds, bears to that taken 
from them by evaporation.” In support of this view, Mr. Straugways, quoting 
Pliny, further shows that such was the opinion of the ancients. “ Sed in Carcinite 
Taurica incipit, quondam mari circumfusd et ipsd.” Plin. iv. 12. “ Ad hos confu- 
gerat Mithridates Claudio principe, narravitque Thulos iis esse confines, qui ab 
oriente Caspii maris fauces attingerent : siccari eas eestu recedente .” Plin. vi. 5. 
Though opposed to our own view, which has been already to a great extent ex- 
pressed (p. 314), viz. that elevations to various levels will alone adequately explain 
the phsenomena of the steppe limestones and sandy steppes (both the bottoms of a 
former Caspian), we specially cite these passages to prove, that the opinions which 
have been recently sustained, particularly by French authors, respecting the desic- 
cation of the Caspian and other inland sheets of water by evaporation only, was 
anticipated by the earliest of our contemporaries who wrote upon the geological 
structure of Russia, and who, unacquainted with many of the facts elicited by sub- 
sequent researches, endeavoured to explain existing phsenomena by evidences of 
ancient tradition, which had escaped the notice of his precursors. 
Changes operated by Man. — But besides such great natural alterations of outline 
and the diurnal wear of the surface, there can be no doubt, that man himself has 
produced considerable changes. Thus for a long time most geographers viewed as 
little better than a fable, the tradition or opinion derived both from the features of 
the country, the details of the historians of Alexander the Great, or the recital of 
the old English traveller Jenkinson, that the main stream of the Oxus once flowed 
into the Caspian Sea. 
Humboldt has the merit of bringing out in all its force the high probability of 
such having anciently been the case, and a very modern discovery of M.N. Khani- 
koff has, we think, strengthened his inference. It has been recently ascertained 
that the river Tanghi-Daria (the Orontes of the ancients), which formerly flowed 
into the sea of Aral in a line considerably south of the Jaxartes, was deflected into 
that stream a few years ago by the mere manual operation of the natives (the Kho- 
kans), who fearful that their well-watered tract might fall a prey to their warlike and 
predatory neighbours of Khivah, constructed a dam and turned their liver north- 
