196 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
the vegetable and animEil kingdoms ; and that quantity is depend- 
ent upon the arrangement and the proportions that we see in na. 
ture between the land and the water — between mountain and des- 
ert, river and sea. If the seas and evaporating surfaces were 
changed, and removed from the places they occupy to other 
places, the principal places of precipitation probably would also 
be changed : whole famihes of plants would wither and die for 
want of cloud and sunshine, dry and wet, in proper proportions 
and in due season ; and, with the blight of plants, whole tribes of 
animals would also perish. Under such a chance arrangement, 
man would no longer be able to rely upon the early and the latter 
rain, or to, count with certainty upon the rains being sent in due 
season for seed-time and harvest. And that the rain will be sent 
in due season, we are assured from on high ; and when we recol- 
lect who it is that " sendeth" it, we feel the conviction strong 
within us that He that sendeth the rain has the winds for his 
messengers ; and that they may do his bidding, the land and the 
sea were arranged, both as to position and relative proportions, 
where they are, and as they are. 
408. It should be borne in mind that the southeast trade-winds, 
after they rise up at the equator (Plate I.), have to overleap the 
northeast trade-winds. Consequently, they do not touch the earth 
until near the tropic of Cancer (see the bearded arrows, Plate 
VII.) — more frequently to the north than to the south of it ; but 
for a part of every year, the place where these vaulting southeast 
trades first strike the earth, after leaving the other hemisphere, is 
very near this tropic. On the equatorial side of it, be it remem- 
bered, the northeast trade-winds blow ; on the polar side, what 
were the southeast trades, and what are now the prevailing south- 
westerly winds of our hemisphere, prevail. Now examine Plate 
YII., and it will be seen that the upper half of the Red Sea is 
north of the tropic of Cancer ; the lower half is to the south of 
it; that the latter is within the northeast trade-wind region; the 
former, in the region where the southwest passage winds are the 
prevailing winds. 
409. The River Tigris is probably evaporated from the upper 
half of this sea by these winds ; while the northeast trade-winds 
take up from the lower half those vapors which feed the Nile with 
rain, and which the clouds deliver to the cold demands of thp 
