44 the thermal springs of selangor and malacca, 

 General Nature of the Springs. 



All the springs visited by me and described more fully 

 later on, belong to the class of "Simple Thermal Waters/' viz., 

 they are characterised by a high temperature, but do not con- 

 tain any considerable amount of dissolved mineral matter. 

 This circumstance, and the small amount of lime in the water, 

 seems to indicate that all these springs rise from silicious and 

 not from calcareous tracts, although no strictly reliable relation 

 can ordinarily be established in such cases between the 

 chemical nature of a spring and its ultimate source. The 

 immediate and obvious surroundings of the springs are old 

 granitic formations. This also applies to those springs which 

 are situated in padi swamps, and where granite, though not 

 apparent, is found below the mud surface. In addition to 

 common and porphyritic granite, quartz, as rock and pebbles, 

 diorite, gneiss and greissen (a kind of granite practically 

 free from felspar which often forms the matrix of tin 

 lodes) are found, but limestone is not apparent. The latter 

 remark, however, does not apply to the springs of Ulu 

 Selangor, which I was unable to visit in person. 



The springs themselves appear as pools or puddles of hot 

 water, varying in area from i to 3 or more square yards, and 

 generally fed by two or more distinct streams or jets issuing 

 from holes and crevices in the bottom of the basin. Bubbles of 

 gas are observed continually to emerge with these jets and 

 ascend through the supernatant hot water. These consist 

 essentially of nitrogen and carbon dioxide with a small quan- 

 tity of hydrogen sulphide and traces of hydrogen and 

 marsh gas. The presence of hydrogen sulphide is apparent 

 from the sulphurous smell in the vicinity of the springs 

 and the water itself owes to this gas a slight smell and 

 taste. The beds of the springs consist of granitic rock more 

 or less decomposed on the surface and coated with silicious 

 sinter. The floor of these beds is covered with all kinds of 

 loose vegetable and mineral debris in the form of granular 

 sediment or soft fibrous and gelatinous masses. The latter 

 accumulate in parts and often form a thick continuous layer on 



