992 The Philippine Journal of Science 1921 
is capable of throwing light. This is due frequently to a defi- 
ciency in and lack of breadth of training. How is it to be 
overcome? It is hardly to be expected that the engineer-student 
will be able to include more geology in his already crowded 
courses. That, however, is not necessary, for all that is desired 
is that he realize his limitations and the importance of the 
bearing of geology upon his work and the need for expert advice. 
Some engineers in the Philippines with whom the writer has had 
the pleasure of working showed that they appreciated this fully. 
Others did not, and as a consequence they have left monuments 
to their lack of insight. 
Previous to our experience in the Philippines, Cuba, and Pan- 
ama, Americans had had no extensive contact with the Tropics 
and consequently many of our engineering data were found 
untrustworthy when applied to wholly new and unusual condi- 
tions. An especially good example may be cited in the location 
of our highways and railroads. In the United States we run 
a railroad line up one cafion, over the pass, and down the other 
side by way of another cafion. This has been tried in the Phil- 
ippines, notably in the Benguet Road; the result is that this road 
may have to be abandoned because of excessive cost of mainte- 
nance. In the Tropics, during high water, there is room for but 
one thing in a valley’and that is the stream which occupies it; 
such a feat of engineering as that which has made the Royal 
Gorge and the Denver & Rio Grande Railroad famous is 
absolutely out of the question in the Tropics. 
There is one cardinal rule to be laid down at the outset, namely, 
take nothing for granted; investigate each problem separately. 
Handbooks and set formule are worse than useless; they are 
dangerous. 
GEOLOGICAL AGENTS 
The three most important geological agents are diastrophism, 
vulcanism, and gradation. The last has four important con- 
tributing factors to be considered; namely, a, weathering; ), 
transportation; ¢, corrasion; and d, corrosion. 
Diastrophism.—tThe first of these, diastrophism, denotes the 
up-and-down movements in the outer shell of the earth. Such 
movements are negligible apparently in the older and more 
stable parts of the earth, but even there they occasionally 
manifest themselves as earthquakes. In the newer parts of the 
earth, and particularly along continental borders, they are of 
considerable magnitude and importance. As it happens, many 
of these places are in the Tropics. This is true of both Panama 
