192 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
the north, are within this range. The Persian Gulf and the Red 
Sea, the Mediterranean, the Black, and the Caspian, all fall within 
it. And why are they planted there ? Why are they arranged to 
the northeast and southwest under this lee, and in the very direc- 
tion in which theory makes this breadth of thirsty winds to pre- 
vail ? Clearly and obviously, one of the purposes in the divine 
economy was, that they might replenish with vapor the winds 
which are almost vaporless when they arrive at these regions in 
the general system of circulation. And why should these winds 
be almost vaporless ? They are almost vaporless because their 
route, in the general system of circulation, is such, that they are 
not brought into contact with a water-surface from which the need- 
ful supplies of vapor are to be had ; or, being obtained, the sup- 
plies have since been taken away by the cool tops of mountain 
ranges over which these winds have had to pass. 
397. In the Mediterranean, the evaporation is greater than the 
precipitation. Upon the Red Sea there never falls a drop of rain ; 
it is all evaporation. Are we not, therefore, entitled to regard the 
Red Sea as a make-weight, thrown in to regulate the proportion 
of cloud and sunshine, and to dispense. rain to certain parts of the 
earth in due season and in proper quantities 1 Have we not, in 
these two facts, evidence conclusive that the winds which blow over 
these two seas come, for the most part, from a dry country — from 
regions which contain few or no pools to furnish supplies of vapor ? 
398. Indeed, so scantily supplied with vapor are the winds which 
pass in the general channels of circulation over the water-shed 
and sea-basin of the Mediterranean, that they take up there more 
w'ater as vapor than they deposit. But, throwing out of the ques- 
tion what is taken up from the surface of the Mediterranean itself, 
these winds deposit more water on the water-shed whose drainage 
leads into that sea than they take up from it again. The excess 
is to be found in the rivers which discharge into the Mediterrane- 
an ; but so thirsty are the winds which blow across the bosom of 
that sea, that they not only take up again all the water that those 
rivers pour into it, but they are supposed by philosophers (§ 252) 
to create a demand for an immense current from the Atlantic to 
supply the waste. 
399. It is estimated that three* times as much water as the 
* Vide article " Physical Geography," Encyclopedia Britannica. 
