Four hundred points
have been hypsometrically determined by barometrical measurements, and
for the most part astronomically; so that it has been rendered possible
to delineate the profile above the sea's level of a tract of land
measuring 3,600 miles, with all its inflections, extending from the
north of Kansas to Fort Vancouver and to the coasts of the South Sea
(almost 720 miles more than the distance from Madrid to Tobolsk). As
I believe I was the first who attempted to represent, in geognostic
profile, the configuration of Mexico, and the Cordilleras of South
America,--for the half-perspective projections of the Siberian
traveler, the Abbe Chappe* were based upon mere, and for the most part
on very inaccurate, estimates of the falls of rivers,--it has afforded
me special satisfaction to there find the graphical method of
representing the earth's configuration in a vertical direction, that
is, the elevation of a solid over fluid parts, achieved on so vast a
scale. In the mean latitude of 37 degrees to 43 degrees, the Rocky
Mountains present, besides the great snow-crowned summits, whose height
may be compared to that of the Peak of Teneriffe, elevated plateaux of
an extent scarcely to be met with in any other part of the world, and
whose breadth from east to west is almost twice that of the Mexican
highlands.
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