158 AMAZONIA AND LA PLATA. 



number with the seasons, reach the head of the plateau, over which they plunge 

 into a yawning chasm 280 feet below. At high water the plunge is made at a 

 single drop ; but at other times the water first strikes a ledge projecting about 

 30 feet from the side ; then, after a second drop of 50 feet, it reaches the chasm 

 at a third leap. But what is thus lost in majesty is gained in the element of the 

 unforeseen, and in the bewildering effect produced by several columns of water 

 clashing, rebounding in parabolic curves, radiating volumes of iridescent spj-ay into 

 space. 



The main body of water, representing nearly the whole river, although 

 scarcely more than 50 feet broad, escapes through the channel lying nearest to the 

 right bank. The rest of the stream from the uj^per cataracts rejoins the swirling 

 flood through a narrow bed skirting the base of the enclosing wall. Then the 

 united current rushes into a formidable garganta (gorge) with vertical sides 

 excavated in the live rock, with overhanging ledges, possibly the remains of 

 natural bridges formerly crossing the gorge at spans of from 2fJ0 to 330 feet. 



To view the cataract in its wildest mood, visitors usu illy take their stand in a 

 grotto which has been gradualh' formed by the action of the rising sprav. No 

 other falls present a more surprising diversity of aspects according to the varying 

 condition of the river. Comparisons are naturally made between the North 

 American and this " Brazilian Niagara," and although there is almost a total 

 lack of the umbrageous vegetation one expects to see in this tropical zone, there 

 is also at least so far a complete absence of the unsightly factories by which the 

 northern falls are disfigured. 



Beyond the gorges the S. Francisco continues to descend through a succession 

 of cascades and rapids inaccessible to river craft all the way to Piranhes, where 

 the river flows at a height of not more than 60 feet above sea level. Here it 

 broadens out in the direction of the south-west, entering the sea through two 

 mouths between shady banks of anacardiums, mangoes, and coconut palms. At 

 low water the bar is less than 10 feet deep, and the approach is often endangered 

 by the rocky shallows and breakers one or two miles otf the estuary. The Paulo 

 Affonso falls and gorges are turned on the north bank by a railway connecting the 

 navigable waterways above and below these obstructions.* 



Coast Sireams. 



South of the Rio S. Francicco follow several coast streams rising on the 

 eastern slopes of the Serra dos Airaores or of its offshoots, and consequently 

 greatly inferior in length and drainage area to the main artery. The Paraguassu 

 with its Jaquipe (Jacuhype) affluent falls into a lateral inlet of Todos os Santos 

 Bay ; but at the head of the tidal waters its navigation is arrested by a cascade. 



* Hydrography of the Rio S. Francisco : — 



Total length of mainstream ...... 1,800 miles. 



Area of basin according to Chichko . 



Ha\àgable upper course 



Navigable lower course 



Navigable waterways of the whole basin 



Discharge per second according to Liais 



267.000 square miles. 

 810 miles. 

 135 miles. 

 4,350 miles. 

 99,000 cubic feet. 



