172 TRANSACTIONS OF THE ILLINOIS 



In all respects the phenomena of gradual failing of summer rains, 

 aridity of climate, and diying up of fountains, are similar on the prairies 

 as in the forests. On the Atlantic slope, there is scarcely a mill-owner 

 who is not aware that as the country is cleared up, the springs fail, and 

 the streams gradually, dry up. New phenomena, however, appear. 

 The rains of summer, though fewer, are more deluging and destructive, 

 and freshets, formerly unknown, become common. 



As already stated, all our rivers are suffering from a diminution of 

 water, and indications are thickening, of impending calamities still 

 greater. We are trying to deceive ourselves with the delusion, that our 

 rivers are becoming shallower, because cultivation has facilitated their 

 encroachments on the soil, and that they are only widening their chan- 

 nels. Now this is not the case; and no one can point to a solitary 

 instance that justifies such a hypothesis. In Germany, observations have 

 been made by actual measurements, on the river Elbe, for the last eighty 

 years. The width of the channel has been accurately measured and the 

 volume of water discharged, calculated. In that time the width of the 

 channel has remained the same, but its depth has deci'eased nine inches, 

 and the volume of water discharged is eighteen per cent. less. The 

 records of the observations and measurements, show that the decrease 

 was gi"adual and uniform for every decade. What was the cause of this .'' 

 In the last eighty years, millions of cords of wood and billions of feet of 

 lumber have been cut from the forests and mountains along its sources. 



Facts could be quoted indefinitely to prove that islands as well as con- 

 tinents suffer the same deplorable consequences; long drouths, alternating 

 with deluging rains, waterspouts, hail, and tornadoes. Ti'inidad, 

 Martinique, Cuba, San Domingo, in fact the whole West Indies and 

 Cape Verde Islands, as well as SjDain, Italy, Greece, etc., would afford 

 examples to this effect, but we must forbear. 



There is, however, another class of facts which can not be omitted 

 without impairing the force of the argument and its application. 

 These facts show that a climate, however much degraded, can be 

 restored. 



In the rear of the city of Caraccas, on an elevated plain, the Theo- 

 broma cacao from which chocolate is made, formerly found its most 

 congenial climate, both as to heat and moisture. But to extend the 

 plantations, the whole plain was denuded of its forests. The result was, 

 the rains ceased, and the climate became so arid that the cidtivation had 

 to be abandoned. But nature quickly restored the vesture of the aban- 

 doned plain, and the cultivation of the cacao has been resumed. 

 Farther in the interior and higher up on the mountains, is the valley of 

 Aragua. Having no outlet to the sea, its watei^s collect in a central plain 

 and form Lake Tariqua. In 151^5 the Spaniards founded New Valentia, 

 one and a half miles from the lake. In 1800, when Humboldt visited the 

 city, it was three and a half miles from the lake. In 1740, a fortress was 

 built upon an island (Cabiera) in the lake. When Humboldt was there, 

 Cabiera had become a peninsula. He also found new islands appearing 

 in the lake, and many hillocks on the shore called islands, from once 



