328 THE POPULAR SCIENCE MONTHLY. 



is tlie northern slope. Of the two rivers, the Parana is much the 

 larger, being second only to the mighty Amazon in size. It main- 

 tains an almost uniform width of three-fourths of a mile to a mile, and 

 a depth of 50 to VO feet for 852 miles, in a comparatively direct line 

 from its mouth to the confluence of the Paraguay. Above this point 

 it is not navigable except for small vessels, at certain seasons of the 

 year; but the Paraguay, which is undoubtedly entitled to be consid- 

 ered the main stream, is navigable for 1,CC0 miles farther. The banks 

 of the Parana Guayaza rise only about tw^o feet above the water, but 

 are of firm soil. They are covered with dense forests of a glossy-leaved 

 tree called sieba, somew^hat resembling the laurel, and a thick under- 

 growth of rushes. The scenery retains this general character for 98 

 miles, where a bluff" is sighted on the right or southwest bank of the 

 river. About ten miles higher up, the river rushes with great force 

 through the Straits of Obligado, a pass between two steep bluff's, about 

 half the regular width of the river apart. At this point the stream is 

 150 feet deep. Excepting at this place, the left bank of the river is 

 formed by an immense, low sw^amp, from 15 to 30 miles in width, for 

 253 miles from the mouth, while the right bank, for 100 miles above 

 the straits, is formed by the high table-land of Buenos Ayres. The 

 first cataract of the Parana occurs about 150 miles above the conflu- 

 ence of the Paraguay, and it is this which renders the upper part of 

 the river unnavigable, except for small vessels, during the floods which 

 annually occur. About 550 miles above this cataract are the Falls of 

 Guaira. These are not perpendicular, as Kiagara, but inclined at an 

 angle of about 50° from the horizon, with a fall of 50 feet. Above 

 the falls, the Parana is 4,500 yards wide, from which it suddenly con- 

 tracts between granite walls 70 to 80 yards apart. Into this pass the 

 water rushes w^ith such tremendous fury, that clouds of spray arise and 

 fall in perpetual rain over the neighborhood ; the roar is such that no 

 other sound can be heard, and the listener is made deaf by the thun- 

 der; even the very earth trembles, so that it has become desolate. 



The Uruguay, a great river by itself, is almost insignificant in 

 comparison. At the mouth, its channel is broad and deep, but at 200 

 miles above it dwindles into a torrent six feet deep, flowing through 

 a rocky pass 145 feet wide. It is, however, subject to floods in Sep- 

 tember and October, during which it rises at the rate of three feet per 

 day to 50 feet above the usual low-water line. At this time, the vol- 

 ume of the river is greatly increased by enlargement of the w^ater- 

 ways, and a more than tenfold increase in the velocity of the cur- 

 rent, which, at ordinary times, is about five miles per hour in the pass 

 described. 



The Parana, on the other hand, although^ as w^e have already seen, 

 similarly subject to an annual overflow, displays nothing like the vio- 

 lent fluctuations of supply belonging to the Uruguay. M. Rc-vy tells 

 us that the ordinary annual rise at Kosario, 189 miles from the mouth 



