LAWS OF HEAT. WATER. 95 



tablished between the atmospheric changes of 

 remote countries. Rains in England are often 

 introduced by a south-east wind. " Vapour 

 brought to us by such a wind, must have been 

 generated in countries to the south and east of 

 our island. It is therefore, probably, in the 

 extensive valleys watered by the Meuse, the 

 Moselle, and the Rhine, if not from the more 

 distant Elbe, with the Oder and the Weser, that 

 the water rises, in the midst of sunshine, which 

 is soon afterwards to form our clouds, and pour 

 down our thunder-showers." " Drought and sun- 

 shine in one part of Europe may be as necessary 

 to the production of a wet season in another, 

 as it is on the great scale of the continents of 

 Africa and South America ; where the plains, 

 during one half the year, are burnt up, to 

 feed the springs of the mountains ; which in 

 their turn contribute to inundate the fertile 

 valleys and prepare them for a luxuriant vege- 

 tation."* The properties of water which regard 

 heat make one vast watering-engine of the atmos- 

 mosphere. 



* Howard on the Climate of London, vol. ii. pp. 216, 217. 



