ZOOLOGY: A. a MAYER 
52? 
5 to about 20 fathoms deep. In former times, the island may have 
been submerged about 20 fathoms below its present level, this being 
suggested by the fairly uniform depth of about 20 fathoms off the mouths 
of the harbors of the northern coast, while these harbors themselves 
have the appearance of drowned valleys. 
However this may be, the latest movement of the island has been an 
emergence of about 8 feet above present high-tide level; for a platform 
about 8 feet above high tide juts out to seaward from the base of prac- 
tically every promontory. The shores are strongly cliffed, some of the 
sea-cliffs being 500 feet high. 
Being volcanic and densely forested from summit to shore, it w as- 
thought that rain-water falling upon the island might become so aug- 
mented in acidity as to dissolve the shoreward parts of the surrounding; 
coral reef. This, however, is untrue. The rain-water is indeed acid^ 
ranging from 0.126 to 0.678 X 10~^ However, the streams and springs 
of the island are usually slightly alkaline, due to bicarbonates ; the 
average of 11 of the principal streams and 6 springs being 7.19 PH., 
or 0.645 X 10~^ hydrogen-ion concentration, and the range from 
0.25 X 10-6 to 0.38 X 10"^ 
An analysis of the water from Faagalu stream below the water-falls 
was made by Prof. Alexander H. Phillips, and shows a high percentage 
of chlorine, and bicarbonates and very little ammonia, or nitrates. 
The calcium, magnesium sodium and potassium are more than sufficient 
to hold the bicarbonates, HCO3, in an ionic state. 
The following is an abstract of Professor Phillip's analysis of Faagalu 
stream water. 
Sample taken April 14, 1917 
Free Ammonia 0 . 036 Magnesium (Mg) 2 . 20 
Albuminoid ammonia 0 . 028 Sodium (Na) 6.19 
Nitrogen in nitrites none Potassium (K) 2.16 
Nitrogen in nitrates 0 . 04 Bicarbonate (HCO3) 9 . 60 
Oxygen consumed 2 . 05 Sulphate (SO4) 4 . 06 
Total solids 70 .06 Chlorine (CI) 12 . 00 
Silica (SiOa) 26 . 55 Nitrate (NO3) 17 
Iron(Fe2 O3) are Alumina (AI2O3) 0 . 95 Phosphate (P2O5) 026 
Calcium 3.03 Hydrogen ion concentration of the water 
0.5 X 10-7. 
It is evident that the calcium is too great in proportion to the sodium 
to have been derived from the salt spray, and must therefore have come 
from the rocks or the decaying vegetation of the Island. 
In Oahu, Hawaiian Islands, also, the streams are alkaline, for Dr. 
