1(54 THE PHYSICAL GEOGRAPHY OF THE SEA. 



trades ; and C, the same wind after it has descended in the calm 

 belt of Capricorn, and come out on the polar side thereof, as the 

 rain winds and prevailing northwest winds of the extra-tropical 

 regions of the southern hemisphere. This, as the northeast trades, 

 is the evaporating wind. As the northeast trade-wind, it sweeps 

 over a great waste of waters lying between the tropic of Cancer 

 and the equator. Meeting no land in this long oblique track over 

 the tepid waters of a tropical sea, it would, if such were its route, 

 arrive, somewhere about the meridian of 140° or 150° west, at the 

 belt of equatorial calms, which always divides the northeast from 

 the southeast trade-winds. Here, depositing a portion of its vapor 

 as it ascends, it would, with the residuum, take, on account of di- 

 urnal rotation, a course in the upper region of the atmosphere to 

 the southeast, as far as the calms of Capricorn. Here it descends 

 and continues on toward the coast of South America, in the same 

 direction, appearing now as the prevailing northwest wind of the 

 extra-tropical regions of the southern hemisphere. Traveling on 

 the surface from warmer to colder regions, it must, in this part of 

 its circuit, precipitate more than it evaporates. Now it is a coin- 

 cidence, at least^ that this is the route by which, on account of the 

 land in the northern hemisphere, the northeast trade-winds have 

 the fairest sweep over that ocean. This is the route by which 

 they are longest in contact with an evaporating surface ; the route 

 by which all circumstances are most favorable to complete satura- 

 tion ; and this is the route by which they can pass over into the 

 southern hemisphere most heavily laden with vapors for the ex- 

 tra-tropical regions of that half of the globe ; and this is the sup- 

 posed route which the northeast trade-winds of the Pacific take to 

 reach the equator and to pass from it. Accordingly, if this proc- 

 ess of reasoning be good, that portion of South America between 

 the calms of Capricorn and Cape Horn, upon the mountain ranges 

 of which this part of the atmosphere, whose circuit I am consider- 

 ing as a type, first impinges, ought to be a region of copious pre- 

 cipitation. Now let us turn to the works on Physical Geography, 

 and see what we can find upon this subject. In Berghaus and 

 Johnston — department Hyetography — it is stated, on the author- 

 ity of Captain King, K. N., that upward of twelve feet (one hund- 

 red and fifty-three inches) of rain fell in forty-one days on that 

 part of the coast of Patagonia which lies within the sweep of tlie 



