422 PACIFIC OCEAN. 
which the various curves characterizing the chains of the globe are 
produced. They evince that (1) while straight ranges are of occasional 
occurrence, curved ranges are still more common ; also (2) that curva- 
tures may arise either from a gradual change of trend in the subordinate 
parts, or from the positions of these parts in a series ; and (3) that the 
same great chain may change its direction sixty degrees or more ; and 
consequently (4) the course of a chain can be no evidence of tts age. 
5. Rectangular Intersections of Chains or Parts of Chains.—The 
rectangular intersections of the Sumatra and Java range in the East 
Indies with the ranges from the north, are described with some detail 
on an early page, where we have shown that the trend of the latter is 
determined by the course of the former, the two varying together. 
The same general fact is illustrated by the Feejee and associated 
groups.. The successive great curves along the east of Asia have 
been pointed out as commencing and ending at right angles with 
one another, or nearly so. Many instances of transverse trends of 
islands in the different groups of the Pacific have been pointed out, 
and these are other examples of the tendency to a rectangularity in 
intersecting lines. 
6. Tivo Systems of Trends.—This subject also has been briefly pre- 
sented in our first chapter. We have shown that throughout the 
Pacific, westward and northwestward lnes prevail, and at the same 
time there are some instances of northward and northeastward lines 
in the Ladrones, the ‘Tonga Group, and New Zealand. The rectangu- 
larity in the intersections above alluded to is often closely connected 
with the existence of these two systems. 
We have also mentioned cases of the northeast lines curving around 
from north by northeast to east and west, as the curves on the coast 
of Asia; while also the northwest lines (the New Guinea chain, for 
example) bend around from north through northwest to east and west, 
and again curve northwest and north. 
7. Leaving the Pacific Ocean, we discover throughout the globe, a 
conformity to the system of topography there exemplified. The two 
systems of trends characterize the lines of coasts, and give the forms 
to continents : and the islands of the Atlantic as well as Indian Ocean 
present other examples. What can be more remarkable than to find 
the Western Islands and Canaries trending parallel with the Sand- 
wich Islands, eight thousand miles distant in the Pacific, and these 
with the New Hebrides and New Caledonia, three thousand five 
hundred miles beyond to the southwest ? 
