172 



Land MAG^fETIC Observations, 1905-10 



NORTH AMERICA. 



United States concluded. 



Washington, District of Columbia, 1904 to 1910. Obser- 

 vations for determination of constants and inter- 

 comparisons of standards during seven years have 

 been made at four pier stations, Am, Cm, Ai, and Ci, 

 and an auxiliary station B. The pier stations are 

 in two non-magnetic houses. These houses and 

 stations are west-northwest of offices of the Depart- 

 ment of Terrestrial Magnetism of the Carnegie 

 Institution of Washington in the Ontario Apartment 

 House, and immediately southeast of the National 

 Zoological Park, on the bluff overlooking the bear pit 

 in the southeast part of the park. In 1905 the hut 

 station of the United States Coast and Geodetic 

 Survey in the grounds of that Bureau was also occu- 

 pied. 



Waycross, Georgia, 1905. The U. S. Coast and Geodetic 

 Survey station of 1905, in the north end of town, in 

 the north corner of a small cemetery, was reoccupied. 

 It is 87 feet (26.5 meters) from the fence bounding 

 the lot on the northwest, and 93.5 feet (28.5 meters) 

 from fence on the northeast; marked by a marble post 



24 inches (61 cm.) long set with top 6 inches (15 cm.) 

 below ground, and having a triangular cross section, 

 with sides about 7, 7, and 10 inches (18, 18, and 



25 cm.); a hole drilled in center of top of stone marks 

 the point. 



SOUTH AMERICA. 



Brazil. 



Amazon 1, Amazonas, 1910. On north bank of river and 

 30 feet (9.1 meters) from two large trees standing in 

 the water a few feet from shore. 



Amazon S, Amazonas, 1910. On northeast bank of river, 

 about 10 yards (9 meters) from water's edge, but on 

 ground covered during highest water. 



Amazon 4, Amazonas, 1910. On left bank of river, on 

 ground covered with water during part of year. 



Amazon 5, Amazonas, 1910. On high bank on right side 

 of river. The home of a rubber-gatherer is about 

 100 yards (91 meters) back from the shore. 



Amazon 6, Amazonas, 1910. On a rocky shelf on south 

 bank of river, about 15 yards (14 meters) from edge 

 of bank. 



Amazon 7, Amazonas, 1910. On high south bank of river 

 and just west of a small tributary extending toward 

 southwest; about 5 paces from edge of river bank. 



Amazon 8, Amazonas, 1910. On a sand bar near north 

 bank of river about 2 miles (3 kilometers) above mouth 

 of Japura River. 



Amazon 9, Amazonas, 1910. On a sand bar near south 

 bank of river just east of a small tributary which 

 extends towards the south. 



Amazon 10, Amazonas, 1910. On north bank of river on a 

 mud flat just opposite two islands; covered with water 

 when the river is high. 



Amazon 11, Amazonas, 1910. On northwest bank of river 

 on a large sand bar. 



Amazon 12, Amazonas, 1910. On a sand bar on south 

 bank of river, just across from a few small native huts. 



Amazon IS, Amazonas, 1910. On a sand bar on east 

 bank of river about 2 miles (3 kilometers) above 

 mouth of lea River and just north of a small tributary 

 which extends towards the east. Marked by a stake 

 projecting a foot (0.3 meter) out of ground. 



SOUTH AMERICA. 

 Brazil continued. 



.Amazon 14, Amazonas, 1910. On south bank of river 

 north of city of Sao Paulo de Olivenca. The point is 

 located on a mud shelf which is covered with water 

 when the river is high, and is almost in line with 

 east end of an island and church in city. 



.Amazon 15, Amazonas, 1910. On west bank of river, near 

 north end of large sand bar; the high-water shore-line 

 is about 400 yards (366 meters) farther inland. 



Amazon 16, Amazonas, 1910. On a sand bar on southeast 

 bank of river; the high-water shore-line is about 300 

 yards (274 meters) farther inland. 



Man&os, Amazonas, 1910. Station I is as near as possible 

 to that occupied by the Brazilian Commission in 1903. 

 It is located on west side of Morro des Educandos and 

 near shore of a small bay projecting from the Negro 

 River; about 200 yards (183 meters) from bank of 

 river, SO feet (15.2 meters) from shore of bay at high 

 water, about 52 feet (16 meters) east-southeast of a 

 large tree standing close to shore of bay, and about 

 39 feet (12 meters) south of path leading up the hill 

 from boat landing which is near large tree. It is 

 marked by a wooden stake projecting about 2 inches 

 (5 cm.) above surface of ground. The following true 

 bearings were determined: spire seen through large 

 tree near station, 120 05'.3; flagpole on cupola seen 

 to the left of the wireless telegraph station poles, 

 180. 26'.2. 



Station II is in the vacant square south of the 

 Instituto Benjiman, and *est of the house used by 

 the employees of the Casa Alden. It is located 29 

 paces from fence about garden of Casa Alden, and 

 65 paces from the wall about the garden of the 

 Instituto Benjiman. It is marked by red sandstone 

 with about 3 by 4 inches (8 by 10 cm.) of surface 

 showing above surface of ground. 



Pinlieiro, Para, 1910. Three stations. A, B, and C, were 

 occupied at this point. The stations are situated in 

 the town of Pinhciro on the east bank of the Para 

 River and about 10 miles (16 kilometers) north of the 

 city of Para. Station A is the same as the Brazilian 

 station of 1903. It is on the point of land directly in 

 front of the San Sebastido church and 69.5 meters 

 from its southwest corner; it is about 100 meters in the 

 direction northeast from end of government wharf and 

 about 10 meters from edge of steep river embankment. 

 This station is marked by concrete blocks 28 cm. 

 square by 4i< cm. thick built up to a height of 76 cm. 

 On the top block there is a copper plate bearing the 

 date of the Brazilian observations, name of the 

 observer, latitude, longitude, and magnetic elements, 

 at the time of observation. The exact point is at the 

 edge of copper plate directly over second "R" in the 

 word " Directoria " ; this point is 8.9 cm. from north 

 edge of block and 11.8 cm. from east edge. The 

 following true bearings were determined for station A: 

 large brick chimney in Para, 1 36'. 2; outer gable end 

 of shelter house on pier at Pinheiro, 42 20'.9; tip of 

 spire of San Sebastido Church, 262 50'. 2. Station B 

 is 15.6 meters from station A in the line from Station A 

 to the large brick chimney in Para. Station C is 

 15.85 meters from station B in line from station B to 

 large brick chimney in Para. 



Rio de Janeiro, Federal District, 1910. Three stations, 

 A, B, and C, were occupied at Freitas Beach. They 

 are on the beach about 250 meters west of present 

 terminus of the Ipanema car line from Rio de Janeiro 

 on grass-covered sand above the high-water mark. 

 Station B, the main station, is about 12 meters from 

 edge of grass and about 20 meters from ridge of a small 

 sand hill to the landward. It is marked by a wood 



