Work began north of the Forelands on May 12 and was in progress on June 30. Steamer Patterson.-The survey of Controller Bay, Alaska, was in progress on July 1 and was continued until October 1, when the Patterson went to Cordova and sailed for Seattle on the 15th. The vessel reached Seattle on October 27 and most of the officers were detached and the crew reduced. Repairs were made to the vessel in January and February, and on April 18 she sailed for Cook Inlet via Cordova to get her tender, the launch Alpha. The ship reached Port Graham, Cook Inlet, on May 5, and the survey of the inlet south of the Forelands was begun on May 9. The work was in progress on June 30. Steamer Taku.-The survey of Prince William Sound, Alaska, in the vicinity of Knight Island, was in progress on July 1 and was continued until September 23, when the vessel was taken to Cordova and laid up for the winter. Repairs were made to the Taku April 28 to May 22, and work on the survey of the sound was resumed on May 31 and continued during the remainder of the fiscal year. Steamer Yukon.-The survey of the east coast of Afognak Island, Alaska, was in progress on July 1, and was continued until September 25, when the vessel was hauled out of the water and laid up for the winter. Repairs were made to the Yukon April 19 to May 10 at Kodiak, Alaska, and the vessel sailed on May 12 for Cook Inlet. Hydrographic and topographic work along the east side of Cook Inlet south from the Forelands began on May 17 and was in progress on June 30. GEODETIC WORK. The records of the field parties were examined at the Office in Washington as they were received and an effective supervision of the work was maintained in this way. 66 The Survey made an important contribution to the science of geodesy by the issue of two publications entitled "The Figure of the Earth and Isostasy from Measurements made in the United States and Supplementary Investigation in 1909 of the Figure of the Earth and Isostasy." These two publications are important, because they furnish a determination of the figure and size of the earth of a high grade of accuracy, because the methods of computing and investigating are somewhat novel, and because this investigation has established the fact that in and around the United States the condition called " isostasy" exists. The publication giving the results of the first investigation was available for distribution in August, 1909, and copies were immediately mailed to the members of the International Geodetic Association in anticipation of the meeting of the General Conference of the association in September last. The supplemental investigation, for which a large amount of additional data had become available, confirmed and strengthened the conclusions deduced in the original discussion. It should be borne in mind that practically all of the field work upon which these investigations are based was done to furnish correct geographic positions along the coast and throughout the interior of the country for controlling surveys and engineering works undertaken by the General Government, States, cities, private corporations, and individuals. Another noteworthy event of the year in connection with the geodetic work was the issue of a preliminary publication giving the results of an investigation of the effect of topography and isostatic compensation upon the intensity of gravity. Additional observations have been made and the investigation is in progress. The Texas-California triangulation was continued and 480 kilometers (300 miles) of progress was made. The precise level net of the United States was extended by the addition of 1,260 kilometers (788 miles) and the relative intensity of gravity was determined in 26 selected localities. MAGNETIC WORK. Instructions for magnetic work and the information required by parties in the field were prepared. Supervision of the work was maintained by an examination of the records of the parties in the field as they were transmitted to the Office from time to time as the work progressed. The activity of the Survey in magnetic work may be summarized as follows: OBSERVATORY WORKS. The magnetic observatories at Cheltenham, Md.; Honolulu. Hawaii; Sitka, Alaska; and Vieques, P. R., were kept in continuous operation. The observations at the observatory formerly at Baldwin, Kans., were discontinued on October 22, 1909, and the instruments were transferred to the building recently completed at Tucson, Ariz. Observations at the Tucson Observatory began on November 16 and were continued during the remainder of the fiscal year. At Cheltenham the usual number of magnetic storms were recorded. The one on September 25 was exceptionally severe and caused the greatest variations in the magnetic elements ever recorded at this observatory. Special observations were made in connection with similar work abroad from May 15 to 20, the period during which the earth passed through the tail of Halley's comet, but no definite result was obtained which can be ascribed to the comet's proximity to the earth. MAGNETIC WORK ON LAND. The values of the magnetic elements declination. dip, and intensity were determined at 238 stations, distributed over 39 States and Territies, including Porto Rico and the Philippine Islands, as shown in the following table: The magnetic work done on board the vessels of the Survey is shown in the following table: As usual, the magnetic work at sea was incidental to the regular surveying work of the vessels, and the observations were made when the vessels were en route to and from the different fields of work or when there was a suitable opportunity during the working season. 58169°-C & L 1910- -37 PUBLICATIONS. The publications of the Coast and Geodetic Survey during the fiscal year are given in the following list: Report of the Superintendent of the Coast and Geodetic Survey, showing the progress of the work from July 1, 1908, to June 30, 1909. 184 pages, with the following appendices, also published separately: No. 3. Results of Magnetic Observations made by the Coast and Geodetic Survey between July 1, 1908, and June 30, 1909. Reprint. 76 pp. No. 4. Distribution of the Magnetic Variation in Alaska and adjacent regions for 1910. Reprint. 30 pp. The Figure of the Earth and Isostasy from Measurements in the United States. 178 pp. Supplementary Investigation in 1909 of the Figure of the Earth and Isostasy. 80 pp. 228 pp. 12 pp. Catalogue of Charts, Coast Pilots, and Tide Tables, 1909. 22 pp. Tide Tables for the year 1911. 530 pp. Tide Tables for the Atlantic Coast of the United States, including Canada and the West Indies. Reprint from the Tide Tables for 1911. 180 pp. Tide Tables for the Pacific Coast of the United States, together with a number of foreign ports in the Pacific Ocean. Tables for 1911. 167 pp. United States Coast Pilot, Atlantic Coast. to New York. Fifth edition. 212 pp. United States Coast Pilot, Atlantic Coast. Reprint from the Tide Part IV: From Point Judith Part V: From New York to Chesapeake Bay Entrance. Fourth edition. 166 pp. Alaska Coast Pilot notes from Yakutat Bay to Cook Inlet and Shelikof Strait. Second edition. 82 pp. Parts I-II: From St. Croix edition. 19 pp. Part III: From Cape Ann to 16 pp. United States Coast Pilot, Atlantic Coast. Part VI: Chesapeake Bay and 10 pp. Part VII: From Chesapeake Bay Entrance to Key West. Supplement to third edition. 23 pp. United States Coast Pilot, Atlantic Coast. Part VIII: Gulf of Mexico from Key West to the Rio Grande. Supplement to third edition. 12 pp. Philippine Island Sailing Directions. Section II: Southwest and South Coasts of Luzon and Adjacent Islands from Manila to San Bernardino Strait. Fourth edition. 102 pp. Philippine Island Sailing Directions. Section V: Coast of Mindanao and Adjacent Islands. Third edition. 136 pp. Catalogue of Charts, Sailing Directions, and Tide Tables of the Philippine Islands, 1910. 54 pp. Philipine Islands. Notices to Mariners. Nos. 5, 6, 7, and 8 of 1909 and Nos. 1, 2, 3, and 4 of 1910. A more detailed description of the work of the year with maps. illustrating its progress can be found in my annual report, which is required by law to be submitted to Congress in December of each O. H. TITTMANN,. year. Yours, respectfully, To Hon. CHARLES NAGEL, Secretary of Commerce and Labor. Superintendent. |