220 THE PHYSICAL GEOGRAPHY OF THE SEA. 



CHAPTER XL 



ON THE GEOLOGICAL AGENCY OF THE WINDS. 



Nature regarded as a Whole, ^ 61L — The Dead Sea, 614. — Annual fall of Rain upon 

 less now than formerly, 615. — The Caspian, 617. — The great American Lakes, 622. 

 —Gulf of Mexico, its Depth, 624.— The Effect of cutting off the Gulf Stream, 625. 

 — Uprising of Continents, 627. — The Causes that change the Water-level of a 

 country, 633. — Foot-prints of the Clouds, 638. — Andes rising from the Sea, 640. — 

 Rains for Europe, 651. — Terrestrial Adaptations, 655. — Evaporating Force in the 

 Mediterranean, 661. — Display of Harmony, 663. — The Age of the Andes and Dead 

 Sea compared, 671. 



611. Propeely to appreciate the various offices which the 

 winds and the waves perform, we must regard nature as a whole, 

 for all the departments thereof are intimately connected. If we 

 attempt to study in one of them, we often find ourselves tracing 

 clews which lead us off insensibly into others, and, before we are 

 aware, we discover ourselves exploring the chambers of some oth- 

 er department. 



612. The study of drift takes the geologist out to sea, and re- 

 minds him that a knowledge of waves, winds, and currents, of 

 navigation and hydrography, are closely and intimately connected 

 with his favorite pursuit. 



613. The astronomer directs his telescope to the most remote 

 star, or to the nearest planet in the sky, and makes an observation 

 upon it. He can not reduce this observation, nor make any use 

 of it, until he has availed himself of certain principles of optics ; 

 until he has consulted the thermometer, gauged the atmosphere, 

 and considered the effect of heat in changing its powers of refrac- 

 tion. In order to adjust the pendulum of his clock to the right 

 length, he has to measure the water of the sea and weigh the cartli. 

 He, too, must therefore go into the study of tlic tides ; he must 

 examine the earth's crust, and consider tlic matter of which it is 

 composed, from pole to pole, circumference to centre ; and in doing 

 this, he finds himself, in his researches, right alongside of the nav- 



