The air is remarkably pure and dry. Siccity, indeed,
is its distinguishing feature. That the climate is due to
geographical and meteorological conditions cannot be doubted, but
the effects are unexplainable by any ordinary rules.
The region involved not only embraces Arizona, but also includes
portions of California and Mexico and is commonly known as the
Colorado Desert. Yuma, at the junction of the Gila and Colorado
rivers, is approximately its geographical center. The general
aspect of the country is low and flat and in the Salton sink the
dry land dips several hundred feet below the level of the ocean.
Only by extreme siccity is such land possible when more water
rises in evaporation than falls by precipitation. There are but
few such places in the world, the deepest one being the Dead Sea,
which is about thirteen hundred feet lower than the ocean.
The Colorado Basin is the dry bed of an ancient sea whose shore
line is yet visible in many places upon the sides of the
mountains which surround it. Its floor is composed of clay with
deposits of sand and salt. Strong winds sometimes sweep over it
that shift and pile up the sand in great dunes. The entire
region is utterly bare and desolate, yet by the use of water
diverted from the Colorado river it is being reclaimed to
agriculture.
The rainfall is very scant the average annual precipitation at
Yuma being less than three inches.
Pages:
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151