Baron Leopold Von Buch <m the Subtropical Zone. 133 



river Amazon^ and in French Guiana, the tropical rains are 

 conformable with those on the south side of the equator, not those 

 on the north side, notwithstanding their northern latitude. 



The subtropical zone is admirably characterized in the north- 

 ern part of the old world by the date-tree {Phccnix dactylifera)- 

 If this tree were also found on the opposite side of the Atlantic 

 sea, the whole zone might well be named the Date Zoric. For 

 on the opposite side of its northern limit, the date-tree no longer 

 ripens its fruit; and the tropical rains prevent a single date- tree 

 ripening its fruit beyond its southern limit. Hence this palm 

 does not occur in India, and therefore is not met with in Mo- 

 samblque or Melide. It first appears again in Mekran, in the 

 27° of latitude, where the south-west monsoon ceases ; and be- 

 fore the north-east wind has obtained the ascendancy, at the 

 end of August and the beginning of September, there occurs 

 a time of very continued heat, which is called the Date 

 Kipening \Khoormu Puz), without which the fruit does not 

 acquire its full ripeness. The caravans, in the interior of 

 Africa, provide themselves with dates for many weeks, when 

 they travel from the south to Bilma, in the 18° of latitude. 

 The soil does not prevent the farther -spread of the date, but 

 the tropical rains soon appear. Browne found the Date but 

 rarely in the Darfur, and only with bad fruit. On the Senegal, 

 in Guinea, in the Congo, it is never seen. The Date is as 

 peculiar to this zone, as the Cocoa is rare in it. It is tndy 

 Temarkable how the cocoa trees no longer thrive when the tropi- 

 cal rains cease. Even in Mekran they are no longer met with, 

 and neither on the coasts of the Arabian nor Persian Gulfs. — 

 Another distinguished production of this zone is Ceratoniu sili- 

 ^ua, the Carob-tree. It oversteps in its distribution the 

 northern and southern boundaries, but only in a small degree, 

 and only as a shoot from the zone itself. The tropical rain also 

 prevents its ripening its fruit. Hence we in vain look for it in 

 India. And probably many other trees will be found and de- 

 termined, which require for the growing and ripening of their 

 fruit the intensity and imiform increase of the subtropical heat, 

 and therefore will be characteristic for this zone. 

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