THE SEA AXD THE ATMOSPHERE. 7 



jiortii with its land is thirteen times in excess of the south. In- 

 deed, such is the inequahty in t\ie distribution of land over the 

 surface of the globe that the world may be divided into hemi- 

 spheres consisting, the one with almost all the land in it, except 

 Australia and a sKp of America lying south of a line drawn from 

 the desert of Atacama to Uruguay ; England is the centre of this, the 

 dry hemisphere. The other, or aqueous hemisphere, contains all 

 the gTeat waters except the Atlantic Ocean ; New Zealand is the 

 nearest land to its centre. 



22. This unequal distribution of land, light, air, and Avater is 

 Effects of inequaiitj' suggestive. To it we owc, in a measure, the differ- 

 land and water. cut climatcs of the earth. Were it different, they 

 would be different also ; were it not for the winds, the vapom^s 

 that rise from the sea would fi^om the clouds be retm-ned in showers 

 l)ack to the places in the sea whence they came ; on an earth where 

 no winds blow we should have neither green pastures, still waters, 

 nor running brooks to beautify the landscape. Were there no 

 cmTents in the sea, nor vertical moverjients m the air, the seasons 

 might change, but climates would be a simple affair, depending 

 solely on the dechnation of the sun in the sky. 



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

 Quantity of fresh earth is coutaiucd in the great American lakes ; and 

 iciiel ^" ^^^*^" ' though there be in the northern, as compared with the 

 southern hemisphere, so much less sea sui-face to yield vapour, so 

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

 diink it in, yet the fresh-water courses are far more numerous 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 boiler 



boiler, and northern -i ,-, ,-i ^ , l^ i' on i 



lauds the condenser, and the northcm to the condenser ot the steam- 

 engine. This vast amount of steam or vapour 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 offices of the atmosphere are many, marvellous, and 

 Offices of the atmo- various. Thougli many of them are past finding 

 ^i^'^^'^^- 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. gea first began — when friends were timid and co- 

 labourers few, the excellent Dr. Buist stood up as its fiiend and 



