in THE HOT SPRINGS 



39 



temperature occasionally as low as 64, at other times mineral and 

 thermal, but with a temperature not usually above 95, issue at the 



surface or at the bottom of deep fissures in the old lava flows 



In Oahu, another island of the Hawaiian group, where the volcanic 

 forces have been long extinct, artesian wells have been in extensive 

 use for some years in the irrigation of the sugar-cane plantations. 

 The last water-bearing strata are reached at depths of 400 to 

 500 feet. 1 The subterranean or artesian reservoirs are evidently 

 therefore on a large scale ; yet Oahu is scarcely one-third the size 



of Vanua Levu in Fiji Lastly, I will refer to the numerous 



subterranean streams that issue forth, as cold and thermal springs, 

 from beneath the lavas near and at the Etna coast, as for instance 

 in the vicinity of Acireale. The Etna slopes are in great part 

 deforested, and in consequence soakage is relatively small, and 

 after heavy rains much of the water runs off in the torrents. Whilst 

 in this locality I was impressed with these facts, and I formed the 

 opinion that in ancient times when Etna was well wooded the 

 discharge of subterranean streams at the coast was far greater 

 than at present. 



For these reasons and on other grounds, amongst them notably 

 the absence of recent crateral cavities, I infer that the numerous 

 hot springs are the outflows of subterranean streams, fed originally 

 by the " soakage " arising from a rainfall of at least 200 to 300 

 inches in the mountainous portions of the island. Such subter- 

 ranean streams run probably at considerable depths, emerging, it is 

 likely, as often under the sea as they do on the land. 



Since writing the above I have read in the Journal of the Royal 

 Geographical Society (November 1902), an abstract of a lecture by 

 Prof. Suess on the subject of hot springs and volcanic phenomena. 

 Thermal springs, he holds, are supplied by hypogene waters and do 

 not receive their salts from the sea. Such springs, according to 

 this view, being the survivals of volcanic activity, originate in the 

 depths of the earth's crust and bring water to the surface for the 

 first time, not deriving it from infiltration. It seems almost im- 

 pertinent to suggest a view opposed to that of such a high authority ; 

 but it appears to me that the frequent situation of the Vanua Levu 

 thermal springs along the lines of surface-drainage requires an 

 explanation that does not altogether exclude the agency of 

 infiltration. 



1 At Ewa there are pumping plants capable of supplying 75 million gallons 

 a day, the water being drawn entirely from artesian wells. (Report on Hawaii^ 

 by Dr. Stubbs, bulletin 95, 1901 ; U.S. Department of Agriculture.) 



