Should it, however, be ascertained that the larger amount of loose material spreading over the harbor is derived from some one or other of the drift islands in the bay, the building of sea-walls to stop the denudation may be of greater and more immediate use than any other operation. Again, it is geologically certain that all the drift islands of the harbor have been formed by the encroachment of the sea upon a sheet of drift, which once extended in unbroken continuity from Cape Ann to Cape Cod and farther south. This sheet of drift is constantly diminishing, and in centuries to come, which, notwithstanding the immeasurable duration of geological periods, may be reached, I trust, while the United States still remains a flourishing empire, it will be removed still further; so far indeed, that I foresee the time when the whole peninsula of Cape Cod shall disappear. Under these circ.u.mstances, it is the duty of a wise administration to establish with precision the rate and the extent of this destruction, that the coming generations may be forewarned. In connection with this I would advise the making of a thorough survey of the harbor, to ascertain the extent of rock surface and of drift, and the relative position of the two, with maps to show their relations to the different levels of the sea, whereby the unequal action of the tides upon the various beaches may be estimated.

The zoological side of the question relates to the amount of loose materials acc.u.mulating in consequence of the increase of animal and vegetable life, especially of those microscopic beings which, notwithstanding their extraordinary minuteness, form in course of time vast deposits of solid materials. Ehrenberg has shown that the harbor of Wismar, on the Prussian coast of the Baltic, is filling, not in consequence of the acc.u.mulation of inorganic sediments, but by the rapid increase and decay of innumerable animalcules. To what extent such deposits may acc.u.mulate has also been shown by Ehrenberg, who ascertained, many years ago, that the city of Berlin rests upon a deposit of about eighteen feet in thickness, consisting almost exclusively of the solid parts of such microscopic beings. These two cases may suffice to show how important may be a zoological investigation of the harbor deposits.

I need hardly add that the deposits floated into the harbor, by the numerous rivers and creeks which empty into it, ought to be investigated with the same care and minuteness as the drift materials. This investigation should also include the drainage of the city.

But this is only a small part of the application I would recommend to be made of geological and zoological knowledge, to the purposes of the Coast Survey. The reefs of Florida are of the deepest interest, and the mere geodetic and hydrographic surveys of their whole range would be far from exhausting the subject. It is my deliberate opinion that the great reefs of Florida should be explored with as much minuteness and fullness as the Gulf Stream, and that the investigation will require as much labor as has thus far been bestowed on the Gulf Stream. Here again geological and zoological knowledge is indispensable to the completion of the work. The reef is formed mainly by the acc.u.mulation of solid materials from a variety of animals and a few plants. The relations of these animals and plants to one another while alive, in and upon the reef, ought to be studied more fully than has been the case heretofore, in order to determine with certainty the share they have in the formation of these immense submarine walls so dangerous to navigation. The surveys, as they have been made thus far, furnish only the necessary information concerning the present form and extent of the reef. But we know that it is constantly changing, increasing, enlarging, spreading, rising in such a way and at such a rate, that the surveys of one century become insufficient for the next. A knowledge of these changes can only be obtained by a naturalist, familiar with the structure and mode of growth of the animals. The survey I made about fifteen years ago, at the request of your lamented predecessor, could only be considered as a reconnaissance, in view of the extent and importance of the work. I would, therefore, recommend you to organize a party specially detailed to carry on these investigations in connection with, and by the side of, the regular geodetic and hydrographic survey. Here, also, would geological knowledge be of great advantage to the explorer. In confirmation of my recommendation I need only remind you of a striking fact in the history of our science. More than thirty years ago, before Dana and Darwin had published their beautiful investigations upon the coral reefs, a pupil of mine, the late Armand Gressly, had traced the structure and mode of growth of coral reefs and atolls in the Jura mountains, thus antic.i.p.ating, by a geological investigation, results afterward obtained by dredging in the ocean. The structure of the reefs of our sh.o.r.es is, therefore, more likely to be fully understood by one who is entirely familiar with zoology and geology than by a surveyor who has no familiarity with either of these sciences.

There is another reason why I would urge upon you the application of natural sciences to the work of the survey. The depth of the ocean is a great obstacle to a satisfactory exploration of its bottom. But we know now that nearly all dry land has been sea bottom before it was raised above the level of the water. This is at least the case with all the stratified rocks and aqueous deposits forming part of the earth's crust. Now it would greatly facilitate the study of the bottom of the sea if, after ascertaining by soundings the general character of the bottom in any particular region, corresponding bottoms on dry land were examined, so that by a comparison of the one with the other, both might be better understood. The shoals of the southern coast of Ma.s.sachusetts have been surveyed, and their position is now known with great accuracy; but their internal structure, their mode of formation, is only imperfectly ascertained, owing to the difficulty of cutting into them and examining in situ the materials of which they are composed. Nothing, on the contrary, is easier than to explore the structure or composition of drift hills which are cut through by all our railroad tracks. Now the shoals and rips of Nantucket have their counterparts on the main-land; and even along the sh.o.r.es of Boston Harbor, in the direction of Dorchester and Milton, such shoals may be examined, far away from the waters to which they owe their deposits. Here, then, is the place to complete the exploration, for which soundings and dredgings give only imperfect information.

I need not extend these remarks further in order to satisfy you of the importance of geological and zoological researches in connection with the regular operations of the Coast Survey. Permit me, however, to add a few words upon some points which, as it seems to me, belong legitimately to the Coast Survey, and to which sufficient attention has not yet been paid. I allude, first, to the salt marshes of our sh.o.r.es, their formation and uses, as well as their gradual disappearance under the advance of the sea; second, to the extended low islands in the form of reefs along the coast of the Southern States, the bases of which may be old coral reefs; third, the form of all our estuaries, which has resulted from the conflict of the sea with the drift formation, and is therefore, in a measure, a geological problem; fourth, the extensive deposits of foraminifera along the coast, which ought to be compared with the deposits of tripoli found in many tertiary formations; fifth, the general form and outline of our continent, with all its indentations, which are due to their geological structure. Indeed, the sh.o.r.e everywhere is the result of the conflict of the ocean with the rock formation of the land, and therefore as much a question for geology as geodesy to answer.

Should the preceding remarks induce you to carry my suggestions into practical operation, be a.s.sured that it will at all times give me the greatest pleasure to contribute to the success of your administration, not only by advice, but by actual partic.i.p.ation in your work whenever that is wanted. The scientific men of America look to you for the publication of the great results already secured by the Coast Survey, well knowing that this national enterprise can only be benefited by the high-minded course which has at all times marked your intellectual career.

Ever truly your friend,

L. AGa.s.sIZ.

This year closed for Aga.s.siz with a heavy sorrow. His mother's health had been failing of late, and November brought the news of her death. Separated though they were, there had never been any break in their intercourse. As far as he could, he kept her advised of all his projects and undertakings, and his work was no less interesting to her when the ocean lay between them than when he could daily share it with her. She had an unbounded sympathy with him in the new ties he had formed in this country, and seemed indeed as intimately allied with his later life here as with its earlier European portion.

His own health, which had seemed for a time to have regained the vigor of youth, broke down again in the following spring, and an attack about the region of the heart disabled him for a number of weeks. To this date belongs a short correspondence between Aga.s.siz and Oswald Heer. Heer's work on the Fossil Flora of the Arctics had recently appeared, and a presentation copy from him reached Aga.s.siz as he was slowly regaining strength after his illness, although still confined to the house. It could not have come at a happier moment, for it engrossed him completely, and turned his thoughts away from the occupations which he was not yet allowed to resume.

The book had a twofold interest for him: although in another branch of science, it was akin to his own earlier investigations, inasmuch as it reconstructed the once rich flora of the polar regions as he himself had reconstructed the fauna of past geological times; it clothed their frozen fields with forests as he had sheeted now fertile lands with ice. In short, it appealed powerfully to the imagination, and no child in the tedious hours of convalescence was ever more beguiled by a story-book than he by the pictures which this erudite work called up.

AGa.s.sIZ TO OSWALD HEER.

CAMBRIDGE, May 12, 1868.

MY HONORED COLLEAGUE,

Your beautiful book on the Fossil Arctic Flora reached me, just as I was recovering from a tedious and painful illness. I could, therefore, take it in hand at once, and have been delighted with it. You give a captivating picture of the successive changes which the Arctic regions have undergone. No work could be more valuable, either as a means of opening recent investigations in Paleontology to the larger public, or of advancing science itself. If I can find the time I mean to prepare an abridgment in popular form for one of our reviews. Meantime I have written to Professor Henry, Superintendent of the Smithsonian Inst.i.tution at Washington, that he should subscribe for a number of copies to be distributed among less wealthy establishments. I hope he will do this, and I shall continue to urge it, since my friendly relations with him give me a right so to do. I have, moreover, written to the directors of various prominent inst.i.tutions, in order that your work, so far as is possible for works of that kind, may become known in the United States, and reach such persons as would naturally be interested in it. . .

With friendly remembrance, yours always,

LOUIS AGa.s.sIZ.

The answer is some months later in date, but is given here for its connection.

FROM OSWALD HEER.

ZURICH, December 8, 1868.

MY HONORED FRIEND,

Your letter of last May gave me the greatest pleasure, and I should have answered it earlier had I not heard that you had gone to the Rocky Mountains, and supposed, therefore, that my letter would hardly find you at home again before the late autumn. I will delay writing no longer,--the more so because I have received, through the Smithsonian Inst.i.tution, your great work on the Natural History of the United States. Valuable as it is in itself, it has a double attraction for me as the gift of the author. Accept my warm thanks.

It will always be to me a token of your friendly regard. It gave me great satisfaction to know that my Fossil Arctic Flora had met with your approval. Since then many new facts have come to light tending to confirm my results. The Whymper Expedition brought to England a number of fossil plants, which have been sent to me for examination. I found eighty species, of which thirty-two from North Greenland are new, so that we now know 137 species of Miocene plants from North Greenland (70 degrees north lat.i.tude). It was a real delight to me to find the fruit cup of the Castanea [chestnut]

inclosing three seeds (three Kastanica) and covered with p.r.i.c.kles like the Castanea vesca; and, furthermore, I was able to prove by the flowers, which were preserved with the fruit, that the supposition given in the Arctic Flora (page 106) was correct; namely, that the leaves of the f.a.gus castaneafolia Ung. truly belong to a Castanea. As several fruits are contained in one fruit cup, this Miocene Castanea must have been nearer to the European species (C. vesca) than to the American Castanea (the C. pumila Micha). The leaves have been drawn in the Flora Arctica, and are also preserved in the Whymper collection.

I have received very beautiful and large leaves of the Castanea which I have called C. Ungeri, from Alaska. I am now occupied in working up this fossil Alaskan flora; the plants are in great part drawn, and contain magnificent leaves. The treatise will be published by the Swedish Academy in Stockholm; I hope to send you a copy a few months hence. This flora is remarkable for its resemblance to the European Miocene flora. The liquidambar, as well as several poplars and willows, cannot be distinguished from those of Oeningen; the same is true of an Elm, a Carpinus, and others. As Alaska now belongs to the United States, it is to be hoped that these collecting stations, which have already furnished such magnificent plants, will be farther ransacked. . .Hoping that you have returned safely from your journey, and that these lines may find you well, I remain, with cordial greeting,

Sincerely yours,

OSWALD HEER.

Shortly after Aga.s.siz's recovery, in July, 1868, he was invited by Mr. Samuel Hooper to join a party of friends, tired members of Congress and business men, on an excursion to the West, under conditions which promised not only rest and change, but an opportunity for studying glacial phenomena over a broad region of prairie and mountain which Aga.s.siz had never visited. They were to meet at Chicago, keep on from there to St. Paul, and down the Mississippi, turning off through Kansas to the eastern branch of the Pacific Railroad, at the terminus of which they were to meet General Sherman with ambulances and an escort for conveyance across the country to the Union Pacific Railroad, returning then by Denver, Utah, and Omaha, and across the State of Iowa to the Mississippi once more. This journey was of great interest to Aga.s.siz, and its scientific value was heightened by a subsequent stay of nearly two months at Ithaca, N.Y., on his return. Cornell University was then just opened at Ithaca, and he had accepted an appointment as non-resident professor, with the responsibility of delivering annually a course of lectures on various subjects of natural history. New efforts in behalf of education always attracted him, and this drew him with an even stronger magnet than usual, involving as it did an untried experiment--the attempt, namely, to combine the artisan with the student, manual labor with intellectual work. The plan was a generous one, and stimulated both pupils and teachers. Among the latter none had greater sympathy with the high ideal and broad humanity of the undertaking than Aga.s.siz.* (* Very recently a memorial tablet has been placed in the Chapel at Cornell University by the trustees, recording their grat.i.tude for the share he took in the initiation of the inst.i.tution.)

Beside the enthusiasm which he brought to his special work, he found an added pleasure at Cornell in the fact that the region in which the new university was situated contained another chapter in the book of glacial records he had so long been reading, and made also, as the following letter tells us, a natural sequence to his recent observations in the West.

TO M. DE LA RIVE.

ITHACA, October 26, 1868.

. . .I am pa.s.sing some weeks here, and am studying the erratic phenomena, and especially the formation of the many small lakes which literally swarm in this region, and are connected in various ways with the glacial epoch. The journey which I have just completed has furnished me with a mult.i.tude of new facts concerning the glacial period, the long continuance of which, and its importance with reference to the physical history of the globe, become daily more clear to me. The origin and mode of formation of the vast system of our American rivers have especially occupied me, and I think I have found the solution of the problem which they present. This system reproduces the lines followed by the water over the surface of the ground moraines, which covered the whole continent, when the great sheet of ice which modeled the drift broke up and melted away. This conclusion will, no doubt, be as slow of acceptance as was the theory of the ancient extension of glaciers. But that does not trouble me. For my own part I am confident of its truth, and after having seen the idea of a glacial epoch finally adopted by all except those who are interested in opposing it on account of certain old and artificial theories, I can wait a little till the changes which succeeded that epoch are also understood. I have obtained direct proof that the prairies of the West rest upon polished rock. It has happened in the course of recent building on the prairie, that the native rock has been laid bare here and there, and this rock is as distinctly furrowed by the action of the glacier and by its engraving process, as the Handeck, or the slopes of the Jura. I have seen magnificent slabs in Nebraska in the basin of the river Platte. Do not the physicists begin to think of explaining to us the probable cause of changes so remarkable and so well established? We can no longer evade the question by supposing these phenomena to be due to the action of great currents. We have to do first with sheets of ice, five or six thousand feet in thickness (an estimate which can be tested by indirect measurements in the Northern States), covering the whole continent, and then with the great currents which ensued upon the breaking up of that ma.s.s of ice. He who does not distinguish between these two series of facts, and perceive their connection, does not understand the geology of the Quaternary epoch. . .

Of about this date is the following pleasant letter from Longfellow to Aga.s.siz. Although it has no special bearing upon what precedes, it is inserted here, because their near neighborhood and constant personal intercourse, both at Cambridge and Nahant, made letters rare between them. Friends who see each other so often are infrequent correspondents.

ROME, December 31, 1868.

MY DEAR AGa.s.sIZ,

I fully intended to write you from Switzerland, that my letter might come to you like a waft of cool air from a glacier in the heat of summer. But alas! I did not find cool air enough for myself, much less to send across the sea. Switzerland was as hot as Cambridge, and all life was taken out of me; and the letter remained in the inkstand. I draw it forth as follows.

One of the things I most wished to say, and which I say first, is the delight with which I found your memory so beloved in England.

At Cambridge, Professor Sedgwick said, "Give my love to Aga.s.siz.

Give him the blessing of an old man." In London, Sir Roderick Murchison said, "I have known a great many men that I liked; but I LOVE Aga.s.siz." In the Isle of Wight, Darwin said, "What a set of men you have in Cambridge! Both our universities put together cannot furnish the like. Why, there is Aga.s.siz,--he counts for three."

One of my pleasantest days in Switzerland was that pa.s.sed at Yverdon. In the morning I drove out to see the Gasparins. In their abundant hospitality they insisted upon my staying to dinner, and proposed a drive up the valley of the Orbe. I could not resist; so up the lovely valley we drove, and pa.s.sed the old chateau of the Reine Berthe, one of my favorite heroines, but, what was far more to me, pa.s.sed the little town of Orbe. There it stands, with its old church tower and the trees on the terrace, just as when you played under them as a boy. It was very, very pleasant to behold . . .Thanks for your letter from the far West. I see by the papers that you have been lecturing at the Cornell University.

With kindest greetings and remembrances, always affectionately yours,

H.W.L.

CHAPTER 22.

1868-1871: AGE 61-64.

New Subscription to Museum.

Additional Buildings.

Arrangement of New Collections.

Dredging Expedition on Board the Bibb.

Address at the Humboldt Centennial.

Attack on the Brain.

Suspension of Work.

Working Force at the Museum.

New Accessions.

Letter from Professor Sedgwick.

Letter from Professor Deshayes.

Restored Health.

Ha.s.sler Voyage proposed.

Acceptance.

Scientific Preparation for the Voyage.