Page:The National Geographic Magazine Vol 16 1905.djvu/160

Department of State by the Superintendent as Commissioner of the United States in coöperation with the Commissioner of Great Britain.

The various operations of the magnetic survey of the country show a gratifying progress during the year. The determination of the magnetic declination, dip, and intensity was made in 327 localities, embracing 367 stations, distributed over 24 states and territories and 2 foreign countries. An extensive investigation was made of the marked local disturbances in the vicinity of Juneau, Alaska, 45 stations being occupied for this purpose. In coöperation with the Louisiana Geological Survey, the magnetic survey of the state was completed. Effective coöperation was secured with an expedition sent to the Bahama Islands by the Baltimore Geographical Society, and valuable results were thus obtained without expense to the Survey.

Excellent progress was made in securing magnetic observations at sea during the voyages of the ships of the Survey to and from their fields of work. In the Atlantic and Pacific Oceans 92 results of magnetic declination and 33 results of magnetic dip and intensity were thus obtained, nearly all of them derived from complete swings of the ships forward and back.

Continuous records of the variations of the magnetic elements were secured throughout the year at five magnetic observations situated at Cheltenham, Md.; Baldwin, Kans.; Sitka, Alaska; near Honolulu, Hawaii, and Vieques, P. R. During the year a large number of magnetic storms were recorded, the most remarkable one occurring October 31-November 1.

During the year a bureau of international research in terrestrial magnetism was created by the Carnegie Institution of Washington, with an officer of the Survey, the inspector of magnetic work, in charge as director.

A continuous record of tide observations with self-registering gauges was obtained during the year at 8 stations, including 1 station at Hawaii and 1 in the Philippine Islands, and for a portion of the year at an additional station which was established on the Gulf of Mexico, at Galveston.

The electric tide indicator installed in the Maritime Exchange at Philadelphia continued to give satisfaction. A similar apparatus was installed during the year in the Maritime Exchange at New York.

The tide indicators established for the use of mariners in New York harbor, in the Delaware River at Reedy Island, and in San Francisco Bay continued in operation during the year.

Compass deviation ranges were established by marks placed on the inner Delaware breakwater, which will prove of great value to shipping, as any vessel can now determine the corrections to her compass while swinging at anchor in the national harbor of refuge.

The field work necessary for the revision of two volumes of the United States Coast Pilot, covering the coast from Point Judith, R. I., to Chesapeake Bay entrance, Virginia, was completed.

Hydrographic surveys were made in 16 states and territories, topographic surveys in 9, triangulation in 14, and leveling in 6.

The primary triangulation along the Pacific coast north of San Francisco was continued.

In Alaska a survey was made of Davidson Inlet, work was continued in Prince William Sound, and two vessels were dispatched to make a survey of Kiska harbor, Aleutian Islands.

In Porto Rico hydrographic work was continued in the harbors and bays and offshore.

The experts of our Department of Agriculture are constantly on the hunt for