216 A NATURALIST IN THE PACIFIC CHAP. 



difference, it is true, but it is far less than we might have looked for. 

 At Delanasau on the north coast, less than a hundred feet above the 

 sea, the mean rainfall for seven years (1871-77), according to the 

 observations of Mr Holmes, was 113 inches, and the range 80 

 to 159 inches (see Home's Year in Fiji}. In discussing the 

 origin of the arid-looking plains on the north or lee side of the 

 island in Note 22, I have shown that the explanation is to be found 

 not so much in the rainfall as in the dryness of the air as indicated 

 by the relative humidity. 



The rainfall varies greatly in and around Vanua Levu, but there 

 is little doubt that by far the greatest bulk of the rain is pre- 

 cipitated on the upper weather slopes of the mountainous backbone 

 of the island. Taviuni, which lies off its weather coast, is probably 

 the wettest among the smaller islands of the group. In 1877, when 

 80 inches were recorded by Mr. Holmes at Delanasau on the north 

 side of Vanua Levu and 73 inches at Levuka in the island 

 of Ovalau, 251 inches were measured in Taviuni at Ngara Walu 

 564 feet above the sea ; and in 1875 the rainfall recorded at 

 Taviuni was 212 inches, and at Delanasau 126 inches (Home). 



Fortunately, the Fijian islands have not been long enough 

 occupied by the whites to produce much effect on the rainfall 

 through the destruction of the forests. A significant warning, 

 however, has been given in the vicinity of Levuka. The woods of 

 the hills around the town, as we learn from Mr. Home, were cut 

 down to prevent them from affording shelter to the unfriendly 

 natives of the interior, the result being to reduce the number of 

 rainy days in a few years from 256 to 149 per annum. 



The Tahitian rainfall. The annual rainfall of the coast 

 districts of Tahiti is placed at about 50 inches (EncycL Brit. 

 vol. 23) ; but, as is observed by Nadeaud and Drake del Castillo, the 

 rain-clouds gather round the peaks, and the precipitation is much 

 greater in the interior than at the " littoral," with a corresponding 

 result in a striking difference between the vegetation of the two 

 regions. Probably, therefore, the rainfall for the year on the wooded 

 mountain slopes and at the heads of valleys where the vegetation is 

 most luxuriant would be over 100, and perhaps as much as 150 

 inches in places. (The annual rainfall in Rarotonga is, according 

 to Cheeseman, about 90 inches.) 



It is evident that in the three groups of Hawaii, Fiji, and Tahiti, 

 the rainfall varies greatly with situation and with elevation ; but 

 the contrast is much greater in Hawaii than in Fiji. Thus there 

 would be scarcely any place on the lee side of Vanua Levu where 



