PHYSIOGRAPHY OF THE PHILIPPINE ISLANDS: II. 



Typhoons. — The islands lie in the track of numerous typhoons which 

 often completelj' destroy the crops and reduce the inliabitants to the 

 verge of starvation. The houses are all built of stone for protection 

 against these winds and at the times of typhoons, nets are stretched across 

 the roofs and anchored to the ground. Typhoons of the first, third, and 

 fifth groups, amounting to 63 per cent of the total number, affect the 

 Batanes Islands.* 



Temperature. — Table II gives the mean monthly temperatures for 

 Santo Domingo de Basco compared with that of Maaila for the years 

 1904 and 1906. It will be seen while there is very little difference in 

 the mean temperature, the range is much greater in the Batanes than in 

 Manila, being over 6° for the former and less than 4° for the latter. 



Table II. — 3fean monthly temperatures in Santo Domingo de Basco and in Manila for 



the years 1904 and 1906. 



Month. 



January ___ 

 February __ 



March 



April 



May 



June 



July 



August 



September, 



October 



November. 

 December _ 



Mean 



1904. 



Santo Do- 

 mingo de 

 Basco. 



21.4 

 21.5 

 23.6 

 26.0 

 27.3 

 27.3 

 27.0 

 27.7 

 27.2 

 26.4 

 24.0 

 21.8 



25.1 



25.1 

 25.4 

 26.2 

 26.9 

 27.8 

 27.2 

 26.7 

 26.8 

 26.2 

 26.3 

 25.0 

 23.9 



26.1 



Santo Do- 

 mingo de 

 Basco. 



22.7 

 24.0 

 23.8 

 26.5 

 27.8 

 28.4 

 28.7 

 28.8 

 28.0 

 2.5.9 

 24.5 

 23 



26 



25.1 

 26.1 

 20. 8 

 29.2 

 28.7 

 28.0 

 27.8 

 27.3 

 26.7 

 26.4 

 25.3 

 25. 



26.9 



GEOGRAPHICAL DESCRIPTION. 



The geologic structure upon which the topography of the islands is 

 largely dependent naturally brings the, Batanes into three groups: 



1. The islands consisting in greater part of the older rocks, volcanic 

 agglomerate with basic dikes. To this group belong the Island of Sabtan 

 and southern part of Batan. 



2. The younger volcanic group, consisting of Mount Iraya in Batan, 

 the Island of Inem and the small islands to the north of Isbayat, locally 

 Icnown as the Siayanes. 



3. The coral limestone group, Desquey, Ibujos and most probably 

 Isbayat. 



'Algue, Rev. Jose, .J. S.: The Cyclones of the Far East, Manila (1904), 247. 



