bis. The Coast Survey provides the vessels for these parties, keeps them in repair, fits them out, and provides for current surveying expenses from the appropriation. When steam is used, the coal, wood, oil, &c., are provided by the coast survey. The engineers attached to the steamers are from the navy, and the names of those now on service in the Coast Survey are given in Appendix No. 4 and No. 4 bis. The transportation of officers is paid by the survey, and during the past year has fallen heavily upon it: officers being directed to report by letter, and not, as heretofore, in person, to the Secretary of the Treasury, so that their transportation in joining has been paid from the appropriation for the survey, and not from the naval appropriation. Draughtsmen are provided, while the parties are in the office, from the coast survey appropriation, being allowed as clerks to the chiefs of parties only when afloat. I have found it necessary to include additional items for these expenses in the estimates for next year. Nearly half the officers of each party being detached from the survey as the parties take up their office work, that afloat is always resumed with the disadvantage of inexperience; which makes the work less valuable and more costly, and sometimes prevents the execution, by the chiefs of parties, of as much as they would desire to accomplish. While the obligations of the survey to the officers of the army and navy serving on it are freely and fully acknowledged, it should not be forgotten that, on the other hand, the work serves as a school of practice for them, and thus gives while it receives. The statistics from the records of the Coast Survey office, furnished in the table Appendix No. 5, show the large amount of work done, and of results collected, up to the beginning of 1851. The number of original topographical maps is 301, consisting of 483 sheets; of hydrographical maps 735; and of reduced maps and charts 220. The extent of shore line already surveyed is 11,873 miles. A list of the discoveries and developments made on different parts of the coast is also printed in the Appendix, (No. 6.) As a summary of these was given in my report of last year, I do not propose at this time to repeat it, but merely to call attention to the new results obtained this year, viz: those upon the Nantucket shoals, as shown in the sketch accompanying this report; the minute survey of the rocks in Hellgate and in Buttermilk channel, to mark the changes effected by blasting; the thorough examination of the Chincoteague shoals, near the entrance to the Chesapeake; the examination of the Frying Pan shoals near Cape Fear, and of Cape Fear entrance; the survey of the harbor of refuge of North Edisto, South Carolina; of Tybee bar and Savannah harbor; of Key West; of the mouths of the Mississippi; and of Humboldt and Trinidad bays, in California. The importance of circulating the sketch of Nantucket shoals among our navigators is very great; as, notwithstanding that frequent publications have been made in regard to them, vessels still incautiously approach too near them. Within the past summer one of our national vessels touched upon Davis's New South shoal, the position of which was published in 1846. The extent of the Chincoteague shoals and of the Frying Pan shoal appear to have been very erroneously laid down hitherto, and are now given, as well as the depth of water upon them, in sketches C No. 3, and D No. 8, appended to this report. The harbor of North Edisto, to the south of Charleston, and that of Bull's bay, to the north, furnish safe refuges to vessels finding themselves to leeward of Charleston entrance in bad weather. On this account I have republished, with the present report, the sketch of Bull's bay (E No. 6,) to accompany that of North Edisto, (E No. 7.) The comparison of the present shore line and channel of the entrances to the Mississippi through the Northeast Pass, and the Pass à l'Outre, with the survey made in 1839, is highly instructive, and will be noticed more in detail in the hydrography of Section VIII. The small number of harbors on the western coast, between San Francisco and Columbia river entrance, renders the contribution of the surveys of Trinity bay and Humboldt harbor of the greater relative importance. The charts of the western coast reconnaissance, in three sheets, were engraved, printed and published in twenty working days from the time the drawing was received at the office of the Coast Survey. As the hydrography advances, tidal stations at important points are occupied, and continuous observations made. Self-registering tide gauges are constructing at the office, which will much facilitate the making of these observations. The results obtained in the Gulf of Mexico from the discussion of the tidal observations are of great interest, leading to the establishment of the laws by which the phenomena are regulated, and bringing within the reach of computation phenomena which were supposed by navigators to be due to the effect of the prevailing winds. Provision has been made for extending these observations during the coming season. I have placed in the Appendix to this report (Nos. 7 and 8) a paper read by me before the American Association for the Advancement of Science, on the tides at Cat island, in the Gulf of Mexico, and on a mode of representing the results of observations of tidal currents; (Sketches H, Nos. 2 to 6, inclusive.) The observations for longitude, by astronomical observations, by the transportation of chronometers, and by telegraph, have been continued at various points; and notices will be found of them, in connexion with the several sections of the coast to which they belong. The discrepancy, which I have stated in previous reports, between the results of longitude by moon culminations and occultations, has been greatly reduced by the researches of Myers F. Longstreth, of Philadelphia; and the re-computation of our results, with his coefficients of the lunar theory, will be in the highest degree important. We expect, in this matter, to receive important aid from the Nautical Almanac office, under the direction of Lieutenant Charles H. Davis, United States navy. An account of a second chronometer expedition between Liverpool and Cambridge is given in Section I. At Cambridge, the transits are generally reduced by what has been called by Professor Airy the "American method," as having originated and been brought to its present advanced state in this country; Mr. Bond using an electrical clock and "spring governor," of his invention, for marking the time at Harvard observatory. It is gratifying to national feeling to be able to state that the clock and governor made for the Coast Survey, by Professor Bond and his sons, has received one of the five honorary medals awarded by the commissioners of the late Industrial exhibition. Charleston and Savannah, (see Section V,) Cambridge and Bangor, (see Section I,) have been connected for difference of longitude by telegraph, and our work has been joined in the same way with that of the British government in Nova Scotia. Observations for declination of stars, giving irregular results for latitude, were made by Professor Mitchell, of Cincinnati, with the new declination apparatus of his invention, in 1849; and it is very desirable that they should be continued, with the apparatus as improved. This method has undergone the close scrutiny, and has received the approval, of the American Association for the Advancement of Science. A description by Professor Mitchell is given in the Appendix, No. 9. The work of two more seasons will nearly, or quite, complete the determinations necessary for the appropriate length of the arc of the meridian passing down the Chesapeake, over the space where the measurement of Mason and Dixon was supposed by some to have indicated irregularities in the figure of the earth-while by others the measurement itself was rejected. The telegraphic connexion between New Orleans and Washington for longitude will, it is expected, be completed next year, which will give the measurement of a portion of a parallel on the Gulf of Mexico, hereafter to be materially extended by the ordinary operations of the survey. The examination of the Florida reef, made at my request, last winter, by Professor Agassiz, has developed, as was anticipated, the subject of its origin, growth, present character, and probable future progress, and in the most masterly manner. As it is desirable to give the results entire, in full detail, with drawings, and in an appropriate form, I have suggested that it be made a separate communication by the Treasury Department to Congress. In the mean time, I present from it a description of the topography of the keys and reef, which forms one of the chapters, with extracts from other portions of the report, in the Appendix, No. 10. The scientific details are so admirably interwoven with the body of the practical conclusions, that it has been found impossible to present portions of the report without injury to the whole. One hundred and fifty-eight maps, charts, and preliminary sketches, are now in the hands of the draughtsmen and engravers, or have been published; a list of which is placed in Appendix No. 11, showing the number published, engraved, and in progress. Of these, the following have been engraved during the year to accompany this report, besides nineteen sketches of progress. I.-General hydrographic sketches, &c. 1. Nantucket shoals. 2. Current chart of Boston harbor. 3. Progress of Sandy Hook. 4. Middle Ground, entrance to Chesapeake. 5. Hatteras shoals. 6. Hatteras inlet. 7. Beaufort harbor. 8. Frying-pan shoals. 24 to 26. McArthur's reconnaissance chart, 3 sheets. 27. Mouth of the Columbia. II.-Sketches for location of light-houses, &c. 1. Holmes's Hole. 2. Beacon ranges, New York. 5. Rebecca shoal. 6. Aransas pass. 7. Galveston bay. 8. San Diego. 9. Point Conception. 10. Point Pinos. 11. San Francisco entrance. 12. Humboldt bay. 13. Cape Hancock. Hydrographic notices have been published by authority of the Treasury Department, and distributed within the past year, in relation to the following localities and subjects, important to the navigating interests of the country: 1. On the draught of vessels which can enter the south channel of the Columbia river, Oregon. 2. Sailing directions for entering the Columbia river as far as the harbor of Astoria. 3. Description of the islands and rivers between the harbor of Monterey and mouth of Columbia river. 4. Correction in the position of the Farallones and Point Lobos, entrance to San Francisco bay. 5. Information in relation to North Edisto harbor of refuge, South Carolina. 6. Information in relation to San Diego, Humboldt, and Trinidad harbors, western coast. 7. Extract from Lieutenant Commanding Alden's letter, in relation to Humboldt harbor and Trinidad bay. 8. Report of the latitude and longitude of Point Conception. The list of geographical positions appended to this report (Appendix No. 12) contains the trigonometrical points of the coast survey determined up to July, 1850; and also the positions of a number of permanent objects determined by means of the plane table. The list is accompanied by sketches showing the positions of the points referred to. A preface explains generally the divisions of the coast which are referred to; and, in a popular way, the mode of determining the distances, latitudes, longitudes, and azimuths, which the table contains, their connexion through the figure of the earth, and their variation due to irregularities of figure and density. The degree of approximation which may be expected from the results of the computation, according to the stage of progress towards the final conclusions, is pointed out. The arrangement of the different parts of the table is also fully explained. Great care will be required in the revision of the printing of this useful list; and even with it, errors must be expected, which, however, a subsequent impression will in a considerable degree correct. The act of 3d of March, 1851, required an important class of duties of the Superintendent of the Coast Survey, namely: to provide for the examination of the sites of light-houses, beacons, buoys, &c., for which appropriations were made, and which, in the opinion of the Fifth Auditor, required examination. "SEC. 2. And be it further enacted, That if such person as the Secretary of the Treasury shall designate shall report, in any of the cases herein provided for, that preliminary surveys are necessary to determine the site of a proposed light-house, or light-boat, beacon or buoy, or to ascertain more fully what the public exigency demands, the Secretary of the Treasury shall thereupon direct the Superintendent of the survey of the coast of the United States to perform such duty on the seaboard, and the colonel of the corps of topographical engineers to perform such duty on the northwestern lakes. "SEC. 3. And be it further enacted, That the officer so directed shall forthwith enter upon the discharge of the duty; and, after fully ascertaining the facts, shall report: First, whether the proposed facility to navigation is the most suitable for the exigency which exists; and, second, where it should be placed if the interests of commerce demand it; third, if the thing proposed be not the most suitable, whether it is expedient to make any other kind of improvement; fourth, whether the proposed light has any connexion with other lights, and, if so, whether it cannot be so located as to subserve both the general and the local wants of trade and navigation; and, fifth, whether there be any, and if any, what other facts of importance touching the subject. 1 "SEC. 4. And be it further enacted, That all such reports shall, as speedily as may be, be laid before the Secretary of the Treasury; and if such as to authorize the work, without further legislation, he shall forthwith proceed with it, otherwise such reports shall be laid before Congress at the next ensuing session; but, in all cases when the person designated by the Secretary of the Treasury, under the second section of this act, does not report such preliminary examination as expedient, the provisions of this act shall, without delay, be carried into execution." |