"During our return to Buenos Ayres," continued Frank, "we went a short distance up the Parana, which is longer than the Paraguay River, but smaller in volume. Its banks are higher and more picturesque, but the country bordering the two streams appears to be pretty much the same. The river can be ascended a long distance; in the upper part it can only be navigated by boats of light draught, as it spreads over sand-bars, and is shallow in many places. [Illustration: PARAGUAYAN CART.] "The Parana rises in the mountains back of Rio Janeiro, and its head-springs are not more than one hundred miles from that city. Several streams unite to form this river; where it leaves the mountain region it has a fall which is said, by many travellers, to be inferior to no other in the world, not even to Niagara. Here is the way it is described: "'After collecting the waters of several rivers on both banks, and especially those of the Tieté and Paranapanema from the east, the Parana increases in width until it attains nearly four thousand five hundred yards, a short distance above the falls; then the immense mass of water is suddenly confined within a gorge of two hundred feet, through which it dashes with fury to the ledge, whence it is precipitated to a depth of fifty-six feet. It is computed that the volume of water per minute is equal to one million tons; the velocity of the flood through the gorge is forty miles an hour, and the roar of the cataract is distinctly audible at a distance of thirty miles.' "If we can't have the pleasure of seeing the Guayrá or Salto Grande, as the cataract of the Parana is called, we will console ourselves with the reflection that we have seen Niagara, and are disinclined to believe it has any superior in the world. Any way, it is three times as high as the cataract of the Parana, and if anybody doubts that there is a million tons of water passing over the American and Horseshoe falls every minute he is at liberty to count them." [Illustration: CARLO ANTONIO LOPEZ, FORMER PRESIDENT OF PARAGUAY.] CHAPTER XXVI. RETURN TO BUENOS AYRES.--DIVIDING THE PARTY.--TWO ROUTES TO VALPARAISO.--FRANK'S JOURNEY OVER THE PAMPAS.--MENDOZA.--AT THE FOOT OF THE ANDES. [Illustration: OLIVE BRANCH FROM THE BANKS OF THE PARANA.] On the way down the river Frank and Fred were occupied with their journals and letters, and with many consultations of the map of South America. The day before their arrival at Buenos Ayres Fred made a suggestion to his cousin relative to their future movements, and intimated that he thought it would be approved by the Doctor. "I think so too," replied Frank, "and we'll go and ask him. It is a repetition of our scheme in Africa without half as many difficulties in the way." Finding Dr. Bronson engaged in nothing more absorbing than looking at the distant bank of the river, they unfolded their scheme.