310 MR. H. H. W. PEARSON ON THE 
in Java and Sumatra, Johnston (17) in Central Africa, Bryce (18) 
in S. Afriea, Humboldt (19) and Belt (20) on the Savannahs of 
S. America and Nicaragua, and Warming (21) on the Brazilian 
Campos. 
The experienee of the Ceylon foresters, stated in the Annual 
Reports of Forest-conservancy, confirms the opinion that the 
constant occurrence of the patana-fires is gradually extending the 
area of the patanas in a westerly direction into that previously 
covered by forest. With regard, however, to the origin of the 
patanas as a whole. the case is not so clear; there is a total 
absence of local tradition relating to a time when the main area 
of the Uva patanas was in any marked way different from what 
it is now, and direct evidence of any kind relating to past 
changes is not forthcoming. There is, however, very strong 
reason for believing tbat the combined effects of the peculiar 
climatie conditions of the region and the recurrence of grass- 
fires have caused the disappearanee of a savannah-forest from 
the area lying between 2000 feet and 4500 feet which is now 
covered by patana-vegetation. 
Before considering this question in further detail, a brief 
general account of the elimate of Uva must be given. 
Climate. 
The distribution of rainfall over the central plateau of the 
Island is determined by the central range of hills, which, as has 
been pointed out above, runs in a general N.N. W. direction from 
Kirigalpotta through the plateau for about 40 miles. The pre- 
vailing winds during the two monsoons thus cross the ridge 
transversely. 
The S. W. monsoon commences early in April, and the wind 
increases in force and constancy until the middle of May, when 
the heavier rains of the monsoon commence, and continue until 
the middle of August; the S. W. wind ceases about the end of 
September. During this monsoon, the south-western and most 
fertile part of the Island receives more than one-third of its total 
rainfall. The S.W. wind, having deposited the greater portion 
of its available moisture on the western slopes and summits of the 
central ridge, passes over the lower country to the east as a hot, 
dry, and often violent wind, still however carrying suthicient 
moisture to render fertile the summits of Namunukuli and other 
