Beginning the measurement of the Salt Lake City Base. Perhaps last use of Eimbeck base bar apparatus. Figure No. 7, Appendix No. 12. Part II, Report of the Superintendent ... 1897, p. 774

Duplex bar No. 15 on its trestles. Figure No. 5, Appendix No. 11. Part II, Report of the Superintendent ... 1897, p. 483.

Duplex bars of Eimbeck base measuring instrument in contact. Figure No. 4, Appendix No. 11. Part II, Report of the Superintendent ... 1897, p. 483.

30 centimeter theodolite. Plate I, Fig. No. 7, Appendix No. 8, Report of Superintendent ... 1894, p. 276

Meridian and equal altitude instrument for astronomic observations. Fig. No. 28, Report of Superintendent ... 1867

Sorenson's engraving pantograph. Fig. No. 27, Report of Superintendent ... 1867

20 centimeter theodolite. Plate II, Fig. No. 8, Appendix No. 8, Report of Superintendent ... 1894, p. 276

Tidal indicator erected at Reedy Island on the Delaware River, Delaware. Figure No. 5, Appendix No. 9. Part II, Report of the Superintendent ... 1897, p. 483. This and two other indicators at New York and San Francisco built by C&GS. Face is thirty feet in diameter

Stierle gauge as modified by the Coast and Geodetic Survey. Figure No. 4, Appendix No. 9. Part II, Report of the Superintendent ... 1897, p. 482

Stierle gauge as modified by the Coast and Geodetic Survey. Figure No. 3, Appendix No. 9. Part II, Report of the Superintendent ... 1897, p. 482

Avery's one-roller tide gauge. Figure 2, Appendix No. 9. Part II, Report of the Superintendent ... 1897, p. 481

Saxton self-registering tide gauge - model of 1853. Figure 1, Appendix No. 9. Part II, Report of the Superintendent ... 1897, p. 481

Clock-face view of modified Stierle tide gauge, model of 1896. Plate No. 5 of Appendix No. 7. Part II, Report of the Superintendent ... 1897, p. 318

Modified stierle tide gauge, model of 1896. Plate No. 4 of Appendix No. 7. Part II, Report of the Superintendent ... 1897, p. 318

Saxton self-registering tide gauge, model as of 1897. Plate No. 3 of Appendix No. 7. Part II, Report of the Superintendent ... 1897, p. 318

Magnetic declination and dip station. Observations at Boundary Marker No. 1. This was at the northernmost point on the Alaska-Canada Boundary. Party of J. T. Watkins - transportation by Coast Guard Cutter Bear

Magnetic observations by party of J. T. Watkins. Station was about 10 miles west of East Cape, Siberia. Transportation by Coast Guard Cutter Bear

Magnetic observations by party of M. L. Cleven.

Magnetic observations by party of M. L. Cleven in east-central Alaskan Arctic.

Observing magnetics with transit magnetometer at Station Mir 2. Party off of EXPLORER

Observing absolute value of horizontal component of the Earth's magnetic field.

Measuring absolute value of declination with a declinometer.

Co-tidal lines of the world.

Making magnetic observations for declination.

Chart showing isogonic lines for year 1900. Isogonic lines are lines of equal declination

Magnetic station near El Misti Volcano, Peru. Party of James Baden

Transit magnetometer station.

Transit magnetometer station. Party off of PATHFINDER

Using compass declinometer for magnetic observations. Lt. Benjamin H. Rigg observing. Accompanied MacMillan Arctic Expedition.

Lt. B. H. Rigg making magnetic observations in Canadian Arctic. Accompanied MacMillan Arctic Expedition

Lt. B. H. Rigg preparing to make magnetic observations in Canadian Arctic. Accompanied MacMillan Arctic Expedition

A Z-Variometer. Instrument measures relative changes in vertical component of Earth's magnetism

Magnetic station at Hobhouse Inlet. Party of Joel Campbell

Lt. Charles A. Schoene observing magnetics at Little America IV. Schoene accompanied Operation High Jump

Magnetic observatory at Little America IV. Tent used for absolute observations while center building used for variation

Chart showing isogonic lines for year 1900. Isogonic lines are lines of equal declination

Brown Gravity Meter - a pendulum apparatus.

Brown Gravity Meter pendulum apparatus.

Observing gravity inside the cave at Station Jaggar. Party of E. J. Brown

Gravity and radio apparatus on Necker Island. Observations as part of World Longitude Network. Party of E. J. Brown

Lt. Joseph Lushene observing gravity in Bahamas. Cooperative project with the Navy and F. A. Vening Meinesz

Lt. Carl Aslakson observing gravity during South American expedition.

Measurements in strain in rock at Dugway Proving Ground.

Why the rock was being strained. 1/2 scale explosion at Dugway Proving Ground

Triangulation observations following major earthquake.

Triangulation observations following major earthquake.

Lieutenant Harley Nygren conducting gravity observations for Sandia Corporation.

Reproduction of first map showing magnetic declination in the United States. First published by the Coast Survey in 1856

Underground magnetic observatory built at the University of Wisconsin in 1870's. Built under direction of Coast Survey. Observations made to Coast Survey specifications. One of many academic geophysical observatories built under guidance of C&GS

Magnetic observations along the Yukon River.