REPORT OF THE SUPERINTENDENT, COAST AND GEODETIC SURVEY. DEPARTMENT OF COMMERCE AND LABOR, COAST AND GEODETIC SURVEY, SIR: I have the honor to submit the following statement covering the operations of the Coast and Geodetic Survey for the fiscal year ended June 30, 1910: SUMMARY OF WORK OF THE YEAR. FIELD WORK. The usual progress was made in the collection and preparation for publication in the form of Charts, Coast Pilots, Tide Tables, and Notices to Mariners of all information useful to navigators and relating to the coasts of the United States and under the jurisdiction of the United States. Very satisfactory progress was made in the Philippine Islands, where surveys were made for charting purposes along the unsurveyed portions of the coast, covering 10 per cent of the whole extent of the estimated general coast line of the archipelago. Good progress was made also in charting the unsurveyed coasts of Alaska, the work being confined to the regions where the demand for charts is most urgent. Important improvements were made in the construction and use of the long wire drag, and its length was increased to 8,400 feet when used in open water. The long lengths greatly increase the area possible to be covered in any given time, and consequently decrease the cost of examining harbors and channels of large extent. The improvements were described in a publication issued for the information of hydrographers. Details in regard to the work assigned to the Survey and to the Superintendent as Commissioner representing the United States in recovering and marking the international boundary between the United States and Canada and in the demarcation of the Alaska boundary are given in Appendixes 1 and 2 of the Annual Report submitted to Congress, but are omitted from this compilation. They, however, form the basis of the following general statements. The establishment of reference monuments in the United States along the water boundary between the United States and Canada between Point Roberts and the Pacific Ocean was completed. All these monuments were connected with the coast triangulation. The same boundary was surveyed and monumented from the summit of the Rocky Mountains eastward to the North Fork of Milk River, a distance of 50 miles, and considerable work was done to the east of this point. West of Lake Superior, the boundary was surveyed along Pigeon River to South Fowl Lake, a distance of 30 miles. On the eastern borders of Maine the survey of the boundary was completed from a point 2 miles below Van Buren, Me., to a point in the vicinity of Fort Kent, Me. On the St. Croix River the triangulation along the boundary from the mouth of the river to Butler Islands was completed. The work of all the parties east of the Rocky Mountains was in progress on June 30. In the demarcation of the Alaska boundary a survey was made. and marks were established in the vicinity of the Unuk and Blue rivers in southeastern Alaska, and on June 30 a party was at work in the valley of Salmon River and another party was at work in the region north of the head of Portland Canal. On the one hundred and forty-first meridian the survey of the boundary was completed between the Yukon River and the Natazhat Mountains 200 miles to the southward, and good progress was made in surveying the line to the northward of the river. This work was in progress on June 30. In this connection I wish to emphasize the importance of providing means for a triangulation down the great valley of the Yukon River from the international boundary to the mouth of the river to form the basis for the economic surveys in progress or in contemplation as a much more desirable plan than the coordination and adjustment of such surveys after they are made. Attention has been called to this work in my annual reports for 1908 and 1909, and an appropriation to begin this triangulation should not be delayed any longer. Work at the latitude observatories at Gaithersburg, Md., and Ukiah, Cal., maintained by the International Geodetic Association under my direction, was continued during the year. One officer continued on duty as a member of the Mississippi River Commission, and another was continuously employed in cooperation with the Maryland State Board of Shell Fish Commissioners in making a survey of the natural oyster bars and rocks in the State of Maryland. The work in Calvert County was completed and a report covering the work was prepared and published. This officer was also authorized to supervise the survey of certain portions of the oyster beds in the State of Delaware, as requested by the governor, without expense to the National Government. Buoys were placed on the boundary between the States of Louisiana and Mississippi in Lake Borgne and Mississippi Sound and referred to the marks previously established on shore, as requested by the state authorities, to aid in the enforcement of the state laws relating to oyster culture. The officer in charge of the Survey exhibit at the Alaska-YukonPacific Exposition remained on that duty until the close of the exposition, on October 16. In accordance with a request made by the War Department, an officer was detailed to serve as the representative of the United States on a commission of engineers created to make a survey of a portion of the Military road leading from the Aqueduct Bridge (across the Potomac River) to Fort Myer, Va. The location of a portion of the boundary of this road being in controversy between the United States and the owners of the adjoining property and the case being before the United States court for the eastern district of Virginia for settlement, a special master commissioner in chancery was named to take testimony, and he appointed the commission of engineers mentioned above. The survey was made and a final report was placed on file. In accordance with instructions issued to Civil Engineer R. E. Peary, U. S. Navy, as stated in the previous Annual Report, tide observations were made in the Arctic regions at Cape Sheridan, Cape Columbia, Cape Bryant, Fort Conger, and Cape Morris Jessup, and the records of the work have been placed on file. Valuable information in regard to the tides was obtained, and a discussion of "Arctic Tides" is being made for publication which will embody all the available information on this subject. Astronomic observations to determine latitude, longitude, or azimuth were made in Texas and in Alaska. Observations to determine the relative force of gravity were made with a half-second pendulum at 27 stations distributed as follows: Four in Arizona, one in California, one in the District of Columbia, one in Maine, two in Michigan, two in Minnesota, two in New Mexico, three in New York, one in Nevada, one in North Dakota, one in South Dakota, two in Tennessee, five in Texas, and one in Vermont. The use of an interferometer, suitably modified, to determine the flexure of the pendulum support was continued. The Standard levels were extended in Arizona, New Mexico, Oklahoma, and Texas. Topographic surveys were made in Alaska, California, Hawaii, Maryland, New Hampshire, North Carolina, Philippine Islands, Virginia, and Washington. Triangulation was done in Alaska, California, Delaware, Florida, Hawaii, Maine, Maryland, Massachusetts, Montana, New Mexico, North Carolina, Philippine Islands, Texas, Virginia, and Washington. The recovery of old triangulation stations was continued on the coasts of Connecticut, Florida, Maryland, Massachusetts, and North Carolina. This work was completed on the west coast of Florida. Hydrographic work was done in Alaska, California, Delaware, Florida, Hawaii, Maine, Maryland, Massachusetts, New Hampshire, North Carolina, Philippine Islands, South Carolina, Virginia, and Washington. The examination of the navigable waters on the coast of Maine with the long wire drag was continued and a similar examination of Mayaguez Harbor and approaches in Porto Rico was made. A new edition of the Coast Pilot volume covering the coast from New York to Chesapeake Bay Entrance was prepared and published. The magnetic survey of the country was continued by making observations at 238 stations distributed over 39 States and Territories, including Porto Rico and the Philippine Islands, and numerous observations were made at sea on board the surveying vessels on their cruises to and from their fields of work in various portions of the country. A continuous record of the relative value of the magnetic. elements was obtained at the magnetic observatories maintained by the Survey at Cheltenham, Md., Sitka, Alaska, Honolulu, Hawaii, and Vieques, P. R. Observations were made at Baldwin, Kans., |