Because of the tentative nature of this work it has been deemed 

 desirable to limit it to the central Pacific, an area where islands abound 

 and less interpolation is required. 



Rainfall records are available for many islands, and temperature 

 records for several of them. Whenever necessary, temperature records 

 have been interpolated after having taken latitude and currents into 

 account. 



Precipitation effectiveness had hitherto been used in the assessment 

 of climatic regions on the continents where it has usefully been correlated 

 with vegetation regions (Thornthwaite, 1933). In this case, however, 

 it was necessary to depart from the usual practice and to use precipitation 

 effectiveness over the ocean as a basis for further research. It was also 

 decided to rely on frequencies and on seasonal totals rather than on 

 annual totals as was customarily done. 



The main pattern which emerges from the following analysis is more 

 complex than was earlier anticipated (Schott, 1933). There are the 

 well-known dry tongue, which reaches ^long the Equator as far west 

 as the Gilbert Islands, and the moist tongue, which reaches from the 

 Solomon Islands to Samoa and farther east. However, the eastward 

 extension of the moist tongue is subject to notable seasonal variations. 

 A new region of high moisture is added in the region of Rapa. The Fijis 

 are definitely drier than the New Hebrides, although the distance between 

 the two groups is smaU and their latitude is approximateh' the same. 



93 



