No visit to Rio de Janeiro is complete without an inspection of the botanical gardens, which cannot fail to appeal to all lovers of the beautiful. Immediately upon entering, one is confronted by avenues of stately royal palms, ninety to one hundred feet high. The “mother of the palms,” towering above all the others, is pointed out with pride by the gardeners. It is said that this was the first of the species to be planted, and that all of the others were grown from seed taken from this one plant. There are also attractive little lagoons filled with flowering pond-lilies and fishes, and bordered with graceful travellers’ palms introduced from Madagascar. Rows of bamboo form sheltered lanes where the visitor may seek relief on comfortable benches from the midday sun. The palace Guanabara, dating back to the time of Dom Pedro, was opened for the use of Colonel Roosevelt. Its location is in the most attractive spot imaginable. Sitting at the table in the immense dining-room, one may look down a palm-lined avenue to the blue water of the bay, a half-mile distant; it was through this lane of tall, beautiful trees that Isabella, daughter of the King, drove to her daily bath in the surf. Acting upon the invitation of officials of the Brazilian Government, Colonel Roosevelt abandoned the plans he had made previously and changed the character of the expedition from a zoological to a geographical one. Colonel Rondon, who had been engaged some years in making a survey through Matto Grosso for a telegraph-line, had discovered the headwaters of an unmapped river. This he had called the _Rio da Duvida_, or River of Doubt, for no one knew whither it went. The invitation to explore and map this stream was tendered to Colonel Roosevelt, and he accepted it. We left the colonel at Rio de Janeiro, after making arrangements to meet subsequently, and continued on to Buenos Aires, spending a day _en route_ in Santos, and one in Montevideo, the capital of Uruguay. Although we had read and heard a great deal about the city of Buenos Aires, we were hardly prepared for the pleasant surprise that awaited us. The population of this metropolis of the south is more than a million and a half, and the city presents a clean, dignified appearance. In many respects it is as modern as New York City. There are numbers of tall edifices patterned after our own skyscrapers, large hotels, and theatres. An electric subway was just being opened, and the crowds in the Calle Florida in the late afternoon rival those of Broadway. The climate is cool and agreeable. One of the things that particularly attracted our attention was the presence one day of swarms of dragon-flies flying in a steady stream high above the city; they were blown in by violent winds, or pamperos, which sweep across the level plains country, and gave one the impression of a raging snow-storm.