A JOURNEY IN BRAZIL.
CHAPTER I.
VOYAGE FROM NEW YORK TO RIO DE JANEIRO.
First Sunday at Sea.—Gulf Stream.—Gulf-Weed.—Lectures proposed.—First Lecture: “On the Gulf Stream in the Gulf Stream.”—Aquarium established on board.—Second Lecture.—Rough Sea.—Peculiar Tint of Water.—Third Lecture: Laying out Work of Expedition in Brazil; Distribution of Fishes in Brazilian Rivers; its Bearing on Origin of Species; Collecting of Eggs.—Tropical Sunset.—Fourth Lecture: Plan of Geological Investigations with special reference to Glacial Phenomena in South America.—Flying-Fish.—Fifth Lecture: Glacial Phenomena, continued.—Second Sunday at Sea.—Rough Water.—Sixth Lecture: Embryological Investigations as a Guide to sound Classification.—Seventh Lecture.—Moonlight Nights.—Trade-Winds.—Eighth Lecture: Importance of Precision in Localizing Specimens.—Southern Cross.—Ninth Lecture: Fresh-water Fishes of Brazil.—Easter Sunday.—First Sight of South American Shore.—Olinda.—Pernambuco.—Catamarans.—Tenth Lecture: Methods of Collecting.—Eleventh Lecture: Classification of Fishes, as illustrated by Embryology.—Preparations for Arrival.—Twelfth Lecture: Practical Lesson in Embryology—Closing Lecture: Transmutation Theory; Intellectual and Political Independence.—Resolutions and Speeches.—Singular Red Patches on the Surface of the Sea.
April 2d, 1865.—Our first Sunday at sea. The weather is delicious, the ship as steady as anything on the water can be, and even the most forlorn of our party have little excuse for sea-sickness. We have had service from Bishop Potter this morning, and since then we have been on deck reading, walking, watching a singular cloud, which the captain says is a cloud of smoke, in the direction of Petersburg. We think it may be the smoke of a great decisive engagement going on while we sail peacefully along. What it means, or how the battle ends, if battle it be, we shall not know for two months perhaps.[[2]] Mr. Agassiz is busy to-day in taking notes, at regular intervals, of the temperature of the water, as we approach the Gulf Stream. To-night we cut it at right angles, and he will remain on deck to continue his observations.
April 3d.—The Professor sat up last night as he intended, and found his watch, which was shared by one or two of his young assistants, very interesting. We crossed the Gulf Stream opposite Cape Hatteras, at a latitude where it is comparatively narrow, some sixty miles only in breadth. Entering it at about six o’clock, we passed out of it a little after midnight. The western boundary of the warm waters stretching along the coast had a temperature of about 57°. Immediately after entering it, the temperature began to rise gradually, the maximum being about 74°, falling occasionally, however, when we passed through a cold streak, to 68°. These cold streaks in the Gulf Stream, which reach to a considerable depth, the warm and cold waters descending together in immediate contact for at least a hundred fathoms, are attributed by Dr. Bache to the fact that the Gulf Stream is not stationary. It sways as a whole sometimes a little toward the shore, sometimes a little away from it, and, in consequence of this, the colder water from the coast creeps in, forming these vertical layers in its midst. The eastern boundary is warmer than the western one, for the latter is chilled by the Arctic currents, which form a band of cold water all along the Atlantic shore. Their influence is felt nearly to the latitude of Florida. On coming out of the Gulf Stream the temperature of the water was 68°, and so it continued for an hour longer, after which Mr. Agassiz ceased his observations. To-day some of the gulf-weed was gathered by a sailor, and we found it crowded with life. Hydroids, in numbers, had their home upon it; the delicate branching plumularia and a pretty campanularia, very like some of our New England species; beside these, bryozoa, tiny compound mollusks, crusted its stem, and barnacles were abundant upon it. These are all the wonders that the deep has yielded us to-day, though the pretty Portuguese men-of-war go floating by the vessel, out of reach thus far. Such are the events of our life: we eat and drink and sleep, read, study Portuguese, and write up our journals.
April 4th.—It has occurred to Mr. Agassiz, as a means of preparing the young men who accompany him for the work before them, to give a course of lectures on ship-board. Some preparation of the kind is the more necessary, since much of the work must be done independently of him, as it will be impossible for so large a party to travel together; and the instructions needed will be more easily given in a daily lecture to all, than in separate conversations with each one singly. The idea finds general favor. The large saloon makes an excellent lecture-room; a couple of leaves from the dining-table with a black oil-cloth stretched across them serve as a blackboard. The audience consists, not only of our own company, but includes the few ladies who are on board, Mr. Bradbury, the captain of our steamer, Bishop Potter, some of the ship’s officers, and a few additional passengers, all of whom seem to think the lecture a pleasant break in the monotony of a sea voyage. To-day the subject was naturally suggested by the seaweeds of the Gulf Stream, so recently caught and so crowded with life,—“A lecture on the Gulf Stream in the Gulf Stream,” as one of the listeners suggests. It was opened, however, by a few words on the exceptional character of the position of this scientific commission on board the Colorado.
“Fifty years ago, when naturalists carried their investigations to distant lands, either government was obliged to provide an expensive outfit for them, or, if they had no such patronage, scanty opportunities grudgingly given might be granted them on ordinary conveyances. Even if such accommodation were allowed them, their presence was looked upon as a nuisance: no general interest was felt in their objects; it was much if they were permitted, on board some vessel, to have their bucket of specimens in a corner, which any sailor might kick over, unreproved, if it chanced to stand in his way. This ship, and the spirit prevailing in her command, opens to me a vista such as I never dreamed of till I stood upon her deck. Here, in place of the meagre chances I remember in old times, the facilities could hardly be greater if the ship had been built as a scientific laboratory. If any such occasion has ever been known before, if any naturalist has ever been treated with such consideration, and found such intelligent appreciation of his highest aims, on board a merchant-ship fitted up for purposes of trade, I am not aware of it. I hope the first trip of the Colorado will be remembered in the annals of science. I, at least, shall know whom to thank for an opportunity so unique. This voyage, and the circumstances connected with it, are, to me, the signs of a good time coming; when men of different interests will help each other; when naturalists will be more liberal and sailors more cultivated, and natural science and navigation will work hand in hand. And now for my lecture,—my first lecture on ship-board.”
The lecture was given, of course, specimen in hand, the various inhabitants of the branch of seaweed giving their evidence in succession of their own structure and way of life. To these living illustrations were added drawings on the blackboard to show the transformations of the animals, their embryological history, &c.[[3]] Since the lecture, Captain Bradbury has fitted up a large tank as an aquarium, where any specimens taken during the voyage may be preserved and examined. Mr. Agassiz is perfectly happy, enjoying every hour of the voyage, as well he may, surrounded as he is with such considerate kindness.
April 6th.—Though I took notes, as usual, of the lecture yesterday, I had not energy enough to enter them in my journal. The subject was the Gulf Stream,—the stream itself this time, not the animals it carries along with it. Mr. Agassiz’s late observations, though deeply interesting to himself, inasmuch as personal confirmation of facts already known is always satisfactory, have nothing novel now-a-days; yet the history of the facts connected with the discovery of the Gulf Stream, and their gradual development, is always attractive, and especially so to Americans, on account of its direct connection with scientific investigations carried on under our government. Mr. Agassiz gave a slight sketch of this in opening his lecture. “It was Franklin who first systematically observed these facts, though they had been noticed long before by navigators. He recorded the temperature of the water as he left the American continent for Europe, and found that it continued cold for a certain distance, then rose suddenly, and after a given time sank again to a lower temperature, though not so low as before. With the comprehensive grasp of mind characteristic of all his scientific results, he went at once beyond his facts. He inferred that the warm current, keeping its way so steadily through the broad Atlantic, and carrying tropical productions to the northern shores of Europe, must take its rise in tropical regions, must be heated by a tropical sun.[[4]] This was his inference: to work it out, to ascertain the origin and course of the Gulf Stream, has been, in a great degree, the task of the United States Coast Survey, under the direction of his descendant, Dr. Bache.”[[5]]