will be carried to the banks of the Rio Negro; boats will descend from the sources of the Napo and the Ucuyale, from the Andes of Quito and of Upper Peru, to the mouths of the Orinoco,—a distance which equals that from Timbuctoo to Marseilles.” Such were the anticipations of Humboldt more than sixty years ago; and at this day the banks of the Rio Negro and the Cassiquiare are still as luxuriant and as desolate, as fertile and as uninhabited, as they were then. _January 8th._—Manaos. The necessity for some days of rest, after so many months of unintermitted work, has detained Mr. Agassiz here for a week. It has given us an opportunity of renewing our walks in the neighborhood of Manaos, of completing our collection of plants, and also of refreshing our memory of scenes which we shall probably never see again, and among which we have had a pleasant home for nearly three months. The woods are much more full of flowers than they were when I first became acquainted with their many pleasant paths. Passion-flowers are especially abundant. There is one kind which has a delicious perfume, not unlike Cape Jessamine. It hides itself away in the shade, but its fragrance betrays it; and if you put aside the branches of the trees, you are sure to find its large white-and-purple flowers, and dark, thick-leaved vine, climbing up some neighboring trunk. Another, which seems rather to court than avoid observation, is of a bright red; and its crimson stars are often seen set, as it were, in the thick foliage of the forest. But, much as I enjoy the verdure here, I appreciate, more than ever before, the marked passage of the seasons in our Northern hemisphere. In this unchanging, green world, which never alters from century to century, except by a little more or less moisture, a little more or less heat, I think with the deepest gratitude of winter and spring, summer and autumn. The circle of nature seems incomplete, and even the rigors of our climate are remembered with affection in this continual vapor-bath. It is literally true that you cannot move ten steps without being drenched in perspiration. However, this character of the heat prevents it from being scorching; and we have no reason to change our first impression, that, on the whole, the climate is much less oppressive than we expected to find it, and the nights are invariably cool.