The ascent to the castle was very steep and slippery from the rain, which had fallen uninterruptedly all the morning. A wide and deep fosse ran around the brow of the hill, with perpendicular escarpments, which we crossed on a narrow causeway, evidently of comparatively recent construction. If the work seemed imposing from the river, how much more impressive was it when we looked down from its walls into two tiers of chambers sunk in the rock, and in which tall trees were growing, their topmost branches scarcely reaching to the level on which we stood. We descended by a bomb-proof stairway to the bottom, into what had been the magazine, and into the rocky chambers where the ancient garrison had been quartered, more than ever impressed with the daring and energy of those iron men who had subverted the empires of Montezuma and the Incas; and who, within fifty years after the Discovery, had traversed every part of the continent, from California to La Plata. We went into the chapel; there was the niche in which had stood the cross, and an effigy of “Nuestra Madre de Mercedes,” “Our Mother of Mercy,” and beneath it was the font for holding the holy water. By a passage, protected from shot, we ascended to what is called the tower,—a solid mass of masonry, rising some sixty feet above the lower works, with a parapet embrasured for twelve guns, and now almost as solid and substantial as if built but yesterday. In this climate, where the great corrodent, frost, never reaches, the durability of good masonry is almost incredible. The floor of the tower, with the exception of the centre, which had been broken, probably under the impression that treasure might be concealed there, was as smooth and firm as ever. Upon the western side of the work was the main entrance, the massive buttresses which supported the drawbridge, and a glacis, subsiding to a terrace, which had been the parade ground, garden, and cemetery of the garrison. All around the work on this side was an arched way, and immediately facing the draw, and firmly imbedded in the masonry of the tower, a block of stone, bearing a long inscription, but too much defaced to be perfectly made out. Its purport, however, is, that the castle was _reconstructed_, under royal orders, by the Governor Intendant of Nicaragua and Costa Rica, for the defence of the river, in 1747. How long previously works had existed there is now unknown,—probably from the middle of the sixteenth century. Great but ineffective efforts had evidently been made to dislodge or remove this stone, which bears too potential evidence against the pretensions of one “J. Bull,” to be regarded with favor by any in his interest.