604 DAY AND SHEPHERD WATER AND VOLCANIC ACTIVITY 



part porous in high degree. Above sealevel rain falls almost daily on the 

 island up to elevations of 7,000 or 8,000 feet. Most of this meteoric 

 water is deposited on the windward side 24 of the mountains and the lee- 

 ward portions are desert or nearly so. The Kilauea crater is situated on 

 the flank of Mauna Loa at an elevation of about 4,000 feet above the sea 

 and is exactly on the ridge which separates the region of rainfall from 

 the desert of Kau. It is somewhat misleading to assume with Dana that 

 the rainfall at the crater is comparable with the rainfall at Hilo, the near- 

 est considerable town where meteorologic observations are made. Hilo is 

 to windward of the crater and at sealevel. At the Volcano House, still 

 some 3 miles to windward of Halemaumau, the rainfall tables lately pub- 

 lished by the United States Geological Survey give the annual average for 

 the years 1909-1911 as 78.7 inches at the Volcano House and 136.5 inches 

 at Hilo. It is also true, though it can not yet be supported by measured 

 data, that the rainfall at Halemaumau is even smaller than that recorded 

 at the Volcano House, for at an equal distance to leeward of Halemaumau 

 the country is desert and practically without rainfall. The present crater 

 lies in the midst of this transition zone from 78 inches to zero. Be that 

 as it may, there is a more or less abundant rainfall at Kilauea, even 

 though the aggregate amount is much smaller than has hitherto been 

 supposed. 



There is a further fact of observation w T hich may be cited in this con- 

 nection. AVells have been bored on the sugar plantations at elevations up 

 to 2,000 feet on Hawaii and on the other islands. In these borings water 

 is invariably met with (so far as we were able to learn) at sealevel only. 

 The water is ordinarily fresh, but a heavy draft on it always has the effect 

 of increasing its salt content, and some of the wells have been perma- 

 nently ruined for irrigation purposes by this means. 



So far as the conditions surrounding this volcano are concerned, there- 

 fore, water in some form would seem to be very widely distributed except 

 on the high mountains, and as freely available as silica for active partici- 

 pation iu any form of volcanic activity. In the present preliminary sur- 

 vey of the situation it therefore appears as if any attempt to assign the 

 water found in the lava to one or other of these three conceivable sources, 

 or perhaps better, to justify any specific distribution of it among the three 

 conceivable sources, must be based on assumptions of a somewhat arbi- 

 trary and hypothetical character. Nevertheless, there are some indica- 

 tions which inevitably give direction to the probabilities which an indi- 



24 It will, of course, be recalled that the islands of the Hawaiian group are within the 

 trade-wind belt, and that the direction of the wind is very nearly constant throughout 

 most of the year. 



