740 



vulgar, as order every where astonishes, when 

 we cannot easily ascend to first causes ; as the 

 means of temperature of a long succession of 

 months or years surprise those, who see for 

 the first time a treatise on climates. Rivers that 

 belong entirely to the torrid zone display in their 

 periodical movements that wonderful regularity, 

 which is peculiar to a region where the same 

 wind brings almost always strata of air of the 

 same temperature ; and where the change of the 

 Sun in it's declination causes* every year at the 

 same period a rupture of equilibrium in the elec- 

 tric intensity, in the cessation of the breezes, 

 and the commencement of the season of rains. 

 The Oroonoko, the Rio Magdalena, and the 

 Congo or Zaire, are the only great rivers of the 

 equinoctial region of the globe, which, rising near 

 the equator, have their mouths in a much higher 

 latitude, though still within the tropics. The 

 Nile and the Rio de la Plata direct their course 

 in the two opposite hemispheres, from the torrid 

 zone toward the temperate 



* See the theory which I explained above, vol. iv, p. 409. 



+ In Asia, the Ganges, the Burampooter, and the majestic 

 rivers of Indo-China, direct their course toward the equator. 

 The former flow from the temperate to the torrid zone. This 

 circumstance of courses pursuing opposite directions (toward 

 the equator, and toward the temperate climates') has an influence 

 on the period and the height of the risings, on the nature and 

 variety of the productions on the banks of the rivers, on the 



