Some conception of the difficulty of ascending the rapids of the Castillo may be formed from the fact, that it required the utmost exertion of our men, for nearly three hours, to get “La Granadina,” with no freight, past them. The boat once up, the crew made breakfast; and after glancing over the list of the Californian party, who had not neglected to inscribe their names conspicuously on the walls of the fort, we descended, thoroughly drenched with the rain. I had the toothache, and M—— the rheumatism, for a week, “by way of improvement” on our visit to the Castillo. The commandant of the garrison, having found out who were his visitors, was there to receive us; and from him we learned that we were expected in the interior, and that instructions had gone out from the government to all its officers to treat us with every possible respect, and to afford every facility to our progress. He had accordingly come to put himself “at our disposition.” Being hungry, the colloquy took place, on the part of the representative of El Norte, in the intervals which could be spared from Ben’s broiled ham and coffee. For an appetite, and a corresponding contempt for etiquette, I recommend a three hours’ visit to the Castillo Viejo, before breakfast. A few miles above the Rapides del Castillo, are the Rapides del Toro, which, however, are not strong, and are easily passed. Beyond these the river becomes of very nearly uniform width, and flows with a deep, regular current. This part of the stream is, in fact, a kind of estuary, or extension of Lake Nicaragua. The banks are low, and the feathery palm again appears lining the shores. The whole country on both shores, for a long distance back, is swampy, and in parts covered with water in the rainy season. Quite a number of sluggish streams, nevertheless, flow through it, whose names indicate the character of their banks and the surrounding country. There is the Rio Palo del Arco, “Arched with Trees;” the Rio Poco Sol, “Little Sun;” Rio Roblito, Mosquito, etc. It was on the morning of the sixth day after our departure from San Juan, that the boat was pushed in to the low bank for breakfast, at a point but five miles below the Fort of San Carlos, situated at the head of the river, on the lake. Myriads of water-fowl lined the shores, and never so much as moved from the trees above us while we breakfasted. Among them Ben discovered a majestic black eagle, which he shot. The bird fell near us, but as we approached him, he threw himself on his back, with open beak, fierce eye, and threatening talons, defiant to the last. I would have given more than one hard dollar to have undone the wanton act, and sent the proud bird unharmed once more, free to his native mountains.