A06 The Philippine Journal of Science 1921 
sion, when viewed from the stream, of undeveloped regions be- 
yond. Occasionally the monotony of the view is broken by the 
thatched hut of some settler, probably a Chinese storekeeper 
catering to the needs of the people who are opening this watery 
jungle and very rapidly developing it. 
DRAINAGE AND PREPARATION OF THE LAND 
The first step necessary to conquer this fertile area for pro- 
duction is to provide drainage. For this the natural arteries 
leading into the main streams have been insufficient. Artificial 
channels have therefore been dug, until the whole area is now 
a network of small canals and waterways (Plate 1, fig. 2). 
These not only serve for drainage, but also provide a series of 
natural and artificial highways over which the inhabitants canoe, 
transporting themselves and their products to the main streams 
(Plate 1, fig. 3). The large Pasi Cherern Canal, dug within 
comparatively recent years, provides an important means of 
communication between Bangkok, the capital, and the outlying 
districts. It also serves to help drain the land, or to hold back 
the tidewaters for irrigation purposes during the dry season. 
Open waterways serving as drainage channels are of little 
value in carrying off the surplus water when the main streams 
are in flood. Dikes must therefore be provided to hold these 
waters back from the cultivated areas. Before the nipa swamp 
(Plate 2, fig. 1) is made ready for cultivation, it must first be 
encircled by a system of mud dikes thrown up along both main 
and branch streams. In clearing the land along the shore of the 
river a narrow strip, 1.5 to 3 meters wide, next to the stream, 
is left in natural growth (Plate 2, fig. 2). Beyond this strip 
a small, shallow basin, 1 to 1.5 meters in width, is dug, the earth 
from which is thrown to the inside of the plot, forming a raised 
embankment a meter or less higher than the surface of the 
interior beds (Plate 2, fig. 2). Along the smaller waterways 
the extra strip of land and the basin are dispensed with, and 
the dikes are constructed next to the streams. 
The plot is then laid out for a series of raised beds and open 
ditches. The beds encircling the plot are usually parallel to 
the streams and a meter or so wider than those within the plot. 
This allows an extra strip for the raised or diked portion which 
is sometimes held in place by a row of trees, possibly the jak, 
Artocarpus integra (Raderm.) Merr. (Artocarpus integrifolia 
Linn.), planted along the inside ridge. On the inner side of this 
row of trees, the ridge portion gradually slopes off to the level 
s 
