154 
THE PHYSICAL GEOGRAPHY OF THE SEA. 
ure of the most stupendous works of solid masonry that man has 
ever seen — the coral islands of the sea. 
294. And thus, by a process of reasoning which is perfectly 
philosophical, we are irresistibly led to conjecture that there are 
regular and certain, if not appointed channels, through which the 
water travels from one part of the ocean to another, and that those 
channels belong to an arrangement which may make, and, for 
aught we know to the contrary, which does make the system of 
oceanic circulation as complete, as perfect, and as harmonious as 
isthat of the atmosphere or the blood. Every drop of water in 
the sea is as obedient to law and order as are the members of the 
heavenly host in the remotest regions of space. For when the 
morning stars sang together in the almighty anthem, "the waves 
also lifted up their voice ;" and doubtless, therefore, the harmony 
in the depths of the ocean is in tune with that which comes from 
the spheres above. We can not doubt it ; for, were it not so, 
were there no channels of circulation from one ocean to another, 
and if, accordingly, the waters of the Atlantic were confined to the 
Atlantic, or if the waters of the arms and seas of the Atlantic 
were confined to those arms and seas, and had no channels of 
circulation by which they could pass out into the ocean, and trav- 
erse different latitudes and climates — if this were so, then the ma- 
chinery of the ocean would be as incomplete as that of a watch 
without a balance-wheel ; for the waters of these arms and seas 
would, as to their constituents, become, in the process of time, very 
different from the sea waters in other parts of the world, and their 
inhabitants would perish for the want of brine of the right strength 
or of water of the right temperature. • 
295. For instance, take the Red Sea and the Mediterranean by 
way of illustration. Upon the Red Sea there is no precipitation ; 
it is a rainless region ; not a river runs down to it, not a brook 
empties into it ; therefore there is no process by which the salts 
and washings of the earth, which are taken up and held in solution 
by rain or river water, can be brought down into the Red Sea. 
Its salts come from the ocean, and the air takes up from it, in the 
process of evaporation, fresh water, leaving behind all the solid 
matter which this sea holds in solution (§ 239). 
296. On the other hand, numerous rivers discharge into the 
Mediterranean, some of which are filtered through soils and among 
