REPORT ON THE COAST SURVEY

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Mr. Hassler was accordingly appointed; and in the year 1811 he visited Europe for the purpose of obtaining the instruments necessary for his operations, all of which had to be specially constructed; but owing to the disturbed state of the continent, and the subsequent war between England and the United States, his efforts to obtain them were for a long time baffled. He did not return to the United States until the year 1816; and it was not until some time in the year following that a commencement of the work was at length made in the bay and harbor of New York. But the work had hardly begun, before it was suspended in consequence of the failure of Congress to provide funds for its continuance; and in 1818 the law under which the Superintendent had been appointed, was repealed.

From 1819 til 1832 attempts were from time to time made to survey portions of the coast under the direction of the Navy Department. Detached surveys of rivers and harbors were made; and hydrographic reconnaissances of the coast of some of the States; but no general or connected survey of the coast was attempted, nor did the detached surveys yield fruit which, taken as a whole, could be considered creditable to the navy or to the country. The Hon. S.L. Southard, Secretary of the Navy in 1828, in a reply to resolutions of inquiry from the Committee on Naval Affairs, in the House of Representatives, characterized the charts produced by those surveys as expensive and unsafe, pointed out the inefficiency of such a desultory plan of operations, and recommended a recurrence to the law of 1807.

On the repeated representations of Mr. Southard and others, the project of a geodetic survey of the coast conciliated again the favor of Congress in 1832. A small appropriation was then made for carrying out the law of 1807, and the President was authorized to employ in the conduct of the work, such astronomers and other persons as he should judge proper, in addition to officers in the land and naval service. From this time the operations of the Coast Survey passed anew under the charge of Mr. Hassler; and he continued to direct them till his death, which occurred in the year 1843.

In reviewing the history of this early period, it is proper to remember that “the first years were not necessarily years of organization and instruction. The Superintendent had to systematize methods, to train up assistants, to cause the work to grow from a small beginning, until it comprehended the various operations of a geodetic survey upon the land, and included the hydrography of the adjacent waters. When the results accumulated, it was necessary to provide for their computation and reduction; and also for the preparation of maps and charts upon a plain PLAN suited to our extended coast, and for the engraving of the maps themselves. All these things were new in this country. The amount of knowledge, skill and labor required to overcome these and other difficulties was hardly appreciated. The results show how large an amount of work had been done, and how the work was extending beneficially at the time of Mr. Hassler’s death.”

The condition of the work as Mr. Hassler left it, will be made intelligible by the following brief statement. A base line had been measured on the south side of Long Island, in the vicinity of New York, the commercial importance of which obviously indicated it as the proper point of beginning. The triangulation had extended eastward to Rhode Island, and southward to the head of Chesapeake bay; the primary triangulation crossing the neck of New Jersey and Delaware, while a secondary triangulation skirted the coast of New Jersey, meeting and inosculating with another series which extended down Delaware bay. The topography had kept pace with the triangulation; and the hydrography of New York bay and harbor, of Long Island sound, of Delaware bay and river, and the off-shore work, from Montauk Point to the capes of the Delaware, were nearly completed.

A reference to the table of statistics in the second part of this report will show that the triangulation covered an area of 9,000 square miles, furnishing determinations of nearly 1,200 stations, for the delineation of 1,600 miles of shore-line; that 168 topographical maps had been surveyed, and 142 hydrographical charts. The work of publication had been organized, and five large charts were engraved, very nearly ready for publication.

The progress thus sketched, although really very considerable, and highly creditable to the late Superintendent, was still felt to be inadequate to the pressing demands of commerce, and clamors arose in Congress against the administration of the Survey, ascribing the slow progress to an unnecessary refinement in the processes employed, and claiming the results to be inadequate to the expenditure. An investigation was accordingly instituted in 1842, by a congressional committee, which, after a severe and unfriendly scrutiny, practically resulted in a complete endorsement of the principles on which the Survey had been conducted by Mr. Hassler. A proviso was attached to the Appropriation Bill in 1843, directing that the Survey be thereafter executed according to a plan or reorganization to be prepared by a board of officers, consisting of the (late) Superintendent, his two principal assistants, the two naval officers in charge of the hydrographical parties, and four officers of the corps of topographical engineers.

The plan adopted by this board in 1843, and invested with the force of law by the preceding legislation, reaffirms the scientific methods proposed by Mr. Hassler as the basis of the work, and provides for the organization of its operations.

EXPANSION AND MODIFICATION OF THE COAST SURVEY UNDER THE PRESENT SUPERINTENDENT

In consequence of the death of Mr. Hassler, which occurred soon afterwards, the responsibility of amplifying and carrying into effect the provisions of the adopted plan devolved mainly upon his successor., the present Superintendent, Alexander Dallas Bache. The appointment of this gentleman was a concession to the universally expressed scientific judgment of the country. It is within the personal knowledge of some members of this committee, that our colleges, learned societies, and men of science, united in one strenuous call upon the executive, to withdraw Professor Bache from the field of more limited usefulness in which he was already distinguished, and to secure to the entire nation the benefit of his great talents and his services. And it is matter of just pride to them, that their elevated estimate of his merits has been so abundantly vindicated by the brilliancy of his official career.

Up to this time, it will be observed, the Survey had been confined entirely to the Atlantic coast, and to the limited portion of that coast embraced between Narraganset bay and Cape Henlopen. No sooner had the new Superintendent been able to form some just estimate of the magnitude of the work in hand, and of the great length of time which it must require for its completion, at its actual rate of progress, and with the existing provision for its prosecution, than he urgently recommended the adoption of a more comprehensive system, according to which the work should be commenced, and carried on independently, in many places at once; each section employing its own base, and making its own geographical determinations; but all designed to form, when completed, a single continuous and unbroken chain of triangulation extending from one end of the coast to the other. At that time Texas had not been annexed, and the western coast was not in the possession of the United States. The proposition of Professor Bache, reduced to a specific form, was to divide the entire coast of the Atlantic and the Gulf of Mexico into eight distinct sections, *[ Since the acquisition of Texas and the extension of the work to the Pacific coast, the number of sections has been increased to eleven.] embracing as nearly as could be estimated, the same length of shore-line in each; and to commence the work in as many of these simultaneously, as Congress could be induced to provide for.

This recommendation was made at the close of the year 1844, and was immediately approved. Accordingly, in the course of the following year, the Superintendent, besides extending the line of Mr. Hassler at both ends, commenced active operations on the coast of Virginia and North Carolina upon the Atlantic, and upon the coast of Alabama and Mississippi in the Gulf of Mexico. Two yeas later the work had been extended to the States of South Carolina, Georgia, Louisiana and Texas; and two years later still the important survey of the reefs and keys of Florida was commenced.

On the annexation of California, the Pacific coast was immediately included in the plan of operations; and such was the vigor with which the work was pushed forward in every quarter, tat Mr. Corwin, then Secretary of the Treasury, in a report communicated to the Senate in 1851, was enabled to show, that a twofold increase of appropriations to the work had produced an increase in the amount of performance, and in the aggregate of the results obtained, more than threefold. And he traced this economy to the division of labor which an increased scale permits, and to the vigorous prosecution of the work at the south and at the north at the same time, whereby the same persons can avail themselves of the best season for operating in the field in each region. The Secretary, at the same time, advised strongly against the reduction of the appropriations, in the diminution of the force employed on the Survey; maintaining that such retrenchments could be made only at a large economical sacrifice.

With this brief statement of the general administrative principles, according to which the present Superintendent has aimed to conduct the operations of the important work confided to him, the committee proceed to consider, in more specific detail, some of the particular methods pursued in its execution, with special notice of those in which an advance has been made upon methods heretofore used in this or similar works, passing afterwards to a review of the results obtained up to the present time.

DETAILS OF COAST SURVEY OPERATIONS UP TO 1858

Under this head, the committee desire to acknowledge their obligations to the obliging assistants in the office of the Coast Survey at Washington, for information courteously rendered in regard to such matters of history and methods of practice as are not fully embraced in the published reports, and to which the personal knowledge of the members of the committee could not be presumed to extend.

MEASUREMENTS OF BASES. – There have been measured in all, up to the date of the present report, nine principal base-lines, two of which are now connected by a primary triangulation. These two are the Fire Island base, on the south side of Long Island, and the Kent Island base, in Chesapeake bay. Both of these, and also a third one in Massachusetts, were measured with the apparatus designed by Mr. Hassler, and fully described by him in the Transactions of the American Philosophical Society, vol. IV.; the measurements being made with iron bars, and by optical contact. Four bars, each two metres in length, were clamped together endwise, forming a combined length of eight metres, and placed in a wooden box suitably stiffened, the ends of the bars projecting a little beyond the box. A powerful microscope, mounted on a suitable stand, was adjusted so as to bring its cross-wires to point at the forward end of the bars, which was defined by the dividing line formed by an abutting piece clamped against it. The box was then carried forward and adjusted in position so as to bring the rear end under the same microscope; another was adjusted over the forward end, and the measurements continued in this way. The temperature of the bars was ascertained, as nearly as may be done by such means, by thermometers placed in contact with the bars. It will be observed that the correction for temperature is a very sensible quantity in a long line; supposing the temperature at which the standard has its determinate length to be 32° Fahr., as is the case with the metre, and the measurement to have been made at an average temperature of 72°, the nominal length of a line of 10 miles would be 4.5 metres, or nearly 15 feet less than the true length expressed in the standard measure. It is highly important, therefore, that the temperature of the bars during the measurement should be accurately ascertained, or else, that the expansion should be compensated, as in the case of a compensation-pendulum. A mercurial thermometer of ordinary form will follow changes of temperature far more quickly than an iron bar of some thickness, owing to the great specific heat of the latter; while the temperature is rising the thermometer will show a higher, and while it is falling a lower temperature than the iron bar will have acquired at the same time, and the measurement is liable to errors arising from this source, unless the errors in both directions are accidentally balanced in the aggregate.

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