§ 23-27. THE SEA AND THE ATMOSPHERE. ^ 



Effects of inequality ivG. To it we owc the different climates of the earth, 

 land and water. Were it different, they would be different also; 

 were it not for the winds, the vapors that rise from the sea would 

 from the clouds be returned in showers back to the places in the 

 sea whence they came; we should have neither green pastures, 

 still waters, nor running brooks to beautify the landscape on an 

 earth where no winds blow. Were there no currents in the sea, 

 the seasons might change, but climates would be a simple affair, 

 depending solely on the declination of the sun in the sk3^ 



23. About two thirds of all the fresh water on the surface of 

 Quantity of fresh the carth is contaiucd in the great American lakes ; 



water in American .^,^.^ ^ 



lakes. and though there be m the northern, as compared 



with the southern hemisphere, so much less sea surface to yield 

 vapor, so much more land to swallow up rain, and so many more 

 plants to drink it in, yet the fresh-water courses are far more nu- 

 merous and copious on the north than they are on the south side 

 of the equator. 



24. These facts have suggested the comparison in which the 

 Southern seas the southcm hemisphere has been likened to the boil- 

 lands the condenser, er aud the northcm to the condenser of the steam- 

 engine. This vast amount of steam or vapor rising up in the 

 extra-tropical regions of the south, expels the air thence, causing 

 the barometer to show a much less weight of atmosphere on the. 

 polar side of 40° S, than we find in corresponding latitudes north. 



25. The ofl&ces of the atmosphere are many, marvelous, and 

 Offices of the atmos- vaHous. Though many of them are past finding 

 P^^^®- out, yet, beautiful to contemplate, they afford most 

 instructive and profitable themes for meditation. 



26. When this system of research touching the physics of the 

 Dr. Buist. sea first began — when friends were timid and co-la- 

 borers few, the learned Dr. Buist stood up as its friend and cham- 

 pion in India ; and by the services he thus rendered entitled him- 

 self to the gratitude of all who with me take delight in the re- 

 sults which have been obtained. The field which it was pro- 

 posed to occupy — the firstlings of which were gathered in this 

 little book — was described by him in glowing terms, colored to 

 nature. They are apropos, and it is a pleasure to repeat them, 

 with such alterations only as experience shall approve — 



27. "The weight of the atmosphere is equal to that of a solid 



