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ZONES AND REGIONS [Pt. Ill, Sect. I 



the greatest luxuriance of growth, than at Roseau, or on the coast generally. 

 St. Kitts does not possess such lofty mountains as Dominica. 



RAINFALL IN THE LESSER ANTILLES. 

 (From Meteorol. Zeitschr., 1886, p. 462.) 



Rainfall at Roseau in Dominica. 

 The mean of 21 years (186 5- 1 88 5) is 



1,901 mm. ; the minimum during this period 



1,309, the maximum 2,690. 



Monthly mean : mm. 



December 145 



January 148 



February 7 1 



March 5 6 



April 61 



May 73 



June 207 



July 266 



August 274 



September 223 



October 176 



November 200 



Rainfall in St. Kitts. 



The mean of 30 years (1856-18S5) is 



1,292 mm.; the minimum 895, the maximum 



2,111. 200 cm. exceeded only in one year. 



Monthly mean : mm. 



December 96 



January 103 



February 48 



March 55 



April 90 



May 98 



June 92 



July 105 



August 144 



September 154 



October 173 



November 134 



The Greater Antilles, Jamaica, Hayti, and Cuba possess partly high-forest, partly thorn- 

 forest or perhaps savannah. It is impossible to give from the available literature any 

 distinct impression of the vegetation of these islands. 



6. CLIMATE OF TROPICAL AFRICA. 



A frequent alternation of forest and savannah reveals itself on the west 

 coast of tropical Africa. 



True desert stops a little south of the tropic of Cancer and is replaced by a still 

 very scanty open woodland vegetation, with Adansonia digitata and Borassus 

 flabelliformis (Saint Louis, 16 N., 16 33' W., with rainfall 42 cm. ; Goree, I4°39' N., 

 17° 24' W., with rainfall of 53 cm.). Tree-growth becomes richer and more luxuriant 

 further south. Round Sierra Leone (rainfall of 319 cm.) plains and mountains are 

 covered with high-forest. On the Ivory and Gold coasts (Elmina, 5 4' N., i°2o' W., 

 with rainfall of 72 cm. ; Christiansborg, 5 32' N., o° 8' W., with rainfall of 58 cm.) the 

 vegetation is again poorer. East of Akra, in the Gulf of Benin, true savannah with 

 fan-palms prevails (Lagos, 9 26' N., 3 30' E., with rainfall of 172 cm., from two years' 

 observations) ; the country at the mouth of the river Niger (4 17' N., 6° 4' E.) and that 

 of Kamerun (4 N., 9 40' E., with rainfall of 249 cm.) and Gabun (o° 22' N., 9 23' E., 

 with rainfall of 226 cm.) are all covered with rain-forest ; in the highlands of Gabun, 

 however, savannah rich in trees predominates. South of the Ogowe (o°4o' S., 9 E.) 

 the savannah gains the mastery even along the coast, and rain-forest is found by rivers 

 and lagoons only. In Jumba, forest (rain-forest ?), interrupted by savannah, reappears 

 up to the mouth of the Kiulu, south of which savannah with fan-palms and baobab- 

 trees predominates (Chinchosho, 5 9' S., 12 4' E., with rainfall of 108 cm.). The last 



