234 The Philippine Journal of Science 1921 
to block the water circulation. All of these conditions must be 
considered, if possible, previous to the digging of the well. 
It is incredible that even at this late day water should be 
sought with a divining rod, yet a few years ago an attempt was 
made to find aftesian water with a divining rod in the city of 
Zamboanga, Mindanao. Water was not found, and an examina- 
tion of the geology of the country showed that very little chance 
existed of a supply being tapped within a reasonable depth in 
the location desired. In spite of some apparently successful in- 
stances of the use of the divining rod, the employment of this 
device may be classed with other pseudo-scientific operations, 
such as palmistry and astrology. 
Probably the Bureau of Public Works has paid more regard 
to the geology of the country than any other engineering organ- 
ization in the Philippines; and, so far as its wells have been dug 
in the Manila central plain, good results have been obtained. 
But the writer wishes to emphasize this fact; that, in spite of 
all the practical experience of a well driller, there are many 
more things to be taken into consideration than simply those 
that pertain to digging the well. 
Some years ago at Olongapo, Luzon, a well was drilled on the 
Naval Reservation ; the writer, when visiting the place, examined 
the cuttings in the drill and found the material to be diorite, 
which is the basal formation of the island and contains very 
little water, having no regular continuous water-passages. The 
well digger drilled here for twenty-two months. No water was 
found, and in the end he lost all his tools in the hole. As the 
driller was paid by the foot, he, of course, did not have to pay 
the bill. 
In parts of the Hawaiian Islands water has been found by 
sinking through the overlying formation, largely consisting of 
lava, to the ash beds that lie buried below. The water here is 
ponded in this loose formation by the coral reefs bordering many 
parts of the Islands. The same conditions, no doubt, could be . 
found in other tropical countries. 
At the present time geologists are engaged in the Hawaiian 
Islands in attempting to locate high level sources of water to be 
brought down for irrigation purposes. Some success has been 
met with by bringing water through tunnels from the rainy 
sides of the various islands to the drier sides. It should be 
pointed out here that if the geologist is expected to predict the 
finding of water in such regions with any degree of certainty 
unfair advantage is being taken of him. The conditions in 
predominantly lava formations are too uncertain to permit of 
