Progress in Surveying 



i i i 



is within the allowable limits of error in 

 levels extending over this distance, is 

 most satisfactory. 



"Work on the opening and remonu- 

 menting of the international boundary be- 

 tween the United States and Canada west 

 of the Rocky Mountains is making satis- 

 factory progress under my direction and 

 that of the Director of the United States 

 Geological Survey, as commissioners on 

 the part of the United States. 



"The demands of the navy for assur- 

 ance that no undiscovered dangers to 

 navigation existed in certain waters was 

 met by the construction of a wire drag 

 1,000 feet long, and a method was devised 

 by which this drag, set to any desired 

 depth, can be pulled through the water 

 over all portions of any bay or harbor. 

 The drag catches and immediately reveals 

 any hidden rock or any danger to naviga- 

 tion. This drag was successfully used in 

 Frenchmans Bay on the coast of Maine. 



"In response to a request from the 

 Isthmian Canal Commission, a survey 

 was made of the Bay of Ljmon and ap- 

 proaches to Colon, in the Canal Zone. 



"The triangulation was extended from 

 Mount Shasta, in California, to Eugene, 

 Oregon ; in Minnesota, from the North 

 Dakota line to Aitkin; in Texas, from 

 Floresville to Alice, and was in progress 

 in Minnesota and in Washington, north 

 of the Columbia River, at the close of the 

 year. The progress along the ninety- 

 eighth meridian was more rapid and at 

 less cost than during any previous year. 



"A continuous record of the variations 

 in terrestrial magnetism was obtained 

 during the year by photographic means 

 at the magnetic observatories at Chelten- 

 ham, Maryland, at Baldwin, Kansas, at 

 Vieques, Porto Rico, at Sitka, Alaska, 

 and at Honolulu, Hawaii. Incidentally 

 meteorological and seismological obser- 

 vations were made at these observatories. 



MAGNETIC STORMS 



"The year was notable by the large 

 number of magnetic storms which sensi- 

 bly affected the compass direction, this 



being the period of maximum sun-spot 

 activity. On the average there have oc- 

 curred two such storms monthly, which 

 deflected the compass by one-quarter of a 

 degree and more. A comparatively large 

 number of earthquake records were also 

 obtained during the year, the most nota- 

 ble one being the Indian earthquake of 

 last April. 



"The magnetic survey of the country 

 was extended by making observations at 

 numerous stations (286) with portable 

 instruments in 41 states and territories. 

 Some magnetic observations were also 

 obtained in the West Indies during the 

 voyages of the Coast and Geodetic steam- 

 ers Bache and Explorer to the Canal 

 Zone and Porto Rico. 



"Valuable results for the improvement 

 and correction of the magnetic charts of 

 the Atlantic Ocean were obtained on the 

 cruises of the Coast and Geodetic Survey 

 steamers Blake and Bache from Baltimore 

 to the Maine coast last summer; also by 

 the Explorer on her cruise to Porto Rico 

 and back, and by the Bache on her trip to 

 the Canal Zone. 



"Similar results for the Pacific Ocean 

 were obtained by the Coast and Geodetic 

 Survey steamers Patterson and Gedney 

 on their respective cruises. In all, mag- 

 netic data were obtained at about 50 dif- 

 ferent points in the Atlantic and Pacific 

 oceans. 



"In this connection mention should also 

 be made of the effective cooperation en- 

 tered into between the Survey and the 

 Carnegie Institution of Washington, and 

 it is expected that most valuable data will 

 be obtained in the Pacific Ocean. This 

 institution has taken up the systematic 

 magnetic survey of the Pacific Ocean. It 

 has chartered a vessel for this purpose 

 and placed it under the command of one 

 of the most experienced officers of the 

 Survey. 



ALASKA 



"In Alaska the survey of Iphegenia 

 Bay, Davidson Inlet, and Sea Otter 

 Sound was continued. A survey was 



