TBANSACTIONS OF SECTION E. 811 



some sheets of the Ordnance Survey maps. The unaatiafactory reudering of these 

 names induced Sir Charles "Wilson some time ago to suggest the revision of the 

 nomenclature of the Highland sheets by a Committee of the Royal Scottish Geo- 

 graphical Society, and of this committee Dr. Burgess has acted as convener. 



[A committee of the Association was subsequently appointed to report on 

 Scottish place-names, with a small grant.] 



3. Bawfall in Formosa and some of the Effects on the Island and Mainland 



of China. By J. Thomson. 



The following notes on the rainfall of Formosa are the result partly of personal 

 observation while exploring the south of the island, and partly of meteorological 

 and such other statistics as I have been able to consult. 



The island affords a striking example of the work of rain within a contracted 

 area in altering the surface of the land, building np plains seawards, and ultimately 

 litting them for tillage and the support of an increasing population. 



It will be necessary to note the geographical position and configuration of the 

 island, ocean currents, temperature, and prevailing winds, in order to make the 

 subject intelligible. 



Formosa lies between 21° and 25° north latitude, while the 121st degree of east 

 longitude divides it into nearly equal parts from north to south. It is over 200 miles 

 long, and its width varies from tifty to eighty miles. It is traversed by a spine of 

 lofty mountains throughout its whole length from north to south, having a maximum 

 altitude of 12,000 feet. 



It will be seen that after the rains the drainage of this chain is necessarily 

 carried over a very small area, and that the changes caused by erosiou and the 

 deposit of detritus must be well defined. The Pacific Gulf Stream, known to the 

 Japanese as * Korosiwo,' flows north on the eastern side, raising the mean tem- 

 perature of Formosa to about ten degrees higher than that of tlie mainland. The 

 prevailing winds throughout the year are the north-east and south-west monsoons. 

 The former begins to blow about the end of October and continues on to April. 



In its passage across the ocean from the north it is charged with moisture 

 taken up from tbe warm Gulf Stream, and coming in contact with the lofty moun- 

 tain barrier of Formosa, it is forced up to a great altitude, where its burden of 

 A'apour is liberated by the lighter and colder air. This is discharged over tbe forest- 

 ' clad heights in copious rain. 



On the eastern side the rain descends through chasms and gorges in torrential 

 streams, and cataracts carry it back to the ocean. The eastern side presents a 

 rocky front to the sea. The denudation of the mountains by erosiou and its effects 

 can hardly be traced on this side of the island, as the detritus is deposited in the 

 deep sea adjoining the cliffs. On the west of the central chain, where the gradient 

 is more gentle, we find an extensive plain, part of which has been built up within 

 the historic era by the detritus washed down from the mountains, and the major 

 part in a similar manner during the Carboniferous period, as may be gathered from 

 extensive coral islands (and other geological formations) which now form part of the 

 low-lying land redeemed from the bed of the ocean. 



But we need go no further back for evidence of the rapid upbudding of the 

 western plain than the date of the Dutch occupation in 1634. 



Two forts were erected — one, Providentia, at the mouth of the Formosa River 

 (Taiwanfu), the other on the island of Taiwan. The former may now be traced 

 within tbe walls of Taiwanfu, more than five miles inland over the plain, while 

 Taiwan with its fort has been long united to the mainland. 



Evidence of how this change has been accomplished exists in the table-lands 

 and spurs of the central range, about fifteen miles inland from Taiwanfu, in the 

 manner in which these lower ' no man's lands,' so named by the Chinese, are cut 

 up and demolished by the drainage of the lofty chain, chasms cut out by 

 torrents during the rainy season, vast funnel-shaped pits where the land has fallen in 

 undermined by water, broad river beds cut deep into the table-lands, their banks 



