Heliotrope setup at camp of lightkeeper. Triangulation party of William M. Scaife

Showing light at Station Northome. Battery powered lights about 110 feet above ground. Triangulation party of Carl Aslakson

Signal lamps

Signal lamp and batteries

Measuring baseline with wooden rods. French expedition to Peru

Irish Ordinance Survey baseline. First to use bi-metallic compensating principal for base line measurement

Use of odometer for measuring distances

Land surveyor using odometer in United States. A private county surveyor

Coast Survey party measuring Key Largo Base. Base Line party of Alexander Dallas Bache

Coast Survey party measuring Epping Plains Base. The last base line measured by Bache. Base Line party of Alexander Dallas Bache

Coast Survey party measuring Epping Plains Base. The last base line measured by Bache. Base Line party of Alexander Dallas Bache

Graded road made to measure Epping Plains Base. Base Line party of Alexander Dallas Bache

Yolo Buggy used to transport and shade base measuring instruments. Yolo Base Line, one of the most accurate measured in the Nineteenth Century. Base Line party of George Davidson

Yolo Buggy with George Davidson. Base Line party of George Davidson. The last time such buggies were used was in 1962

Army surveyor with odometer carriage. Survey of public lands. Odometer worked fairly well on flat ground

Shelton 100-meter comparator -- Making contact. William Bowie on left

At work with No. 17. William Bowie in center with white hat

Shelton 100-meter comparator

Running levels along the Stanfield Base. Base line and astro party of C. V. Hodgson

Measuring base with Invar tape. Tape underway. Base line and astro party of C. V. Hodgson

Off to measure a base with Invar tape. Party of C. G. Quillian

Time and tide waits for no man. Base line measurement in southeast Alaska. Party of C. G. Quillian

It sure is tough to stay dry with the tide coming in. Base line measurement in southeast Alaska. Party of C. G. Quillian

Measuring the Pasadena Base. Measured at accuracy of at least 1 part in 5 million. Measured accurately to help Albert Michelson determine velocity of light. Base line party of Clement L. Garner

Measuring through house on Pasadena Base. Line selected to pass through window and out other side. Base line length was over 20 miles. Base line party of Clement L. Garner

Crossing ravines on stands to keep line horizontal. Pasadena Base measurement. Base line party of Clement L. Garner

Measuring Pasadena Base across wash at foot of San Antonio Canyon. Base line party of Clement L. Garner

Base line measurement with Invar tape. Off Launch ELSIE

Traverse measurements in sub-zero conditions. Making front contact. Traverse party of Casper Durgin

Traverse measurements in sub-zero conditions. Traverse party of Casper Durgin

Making short setup with steel tape at Station Goodman. Triangulation party of E. O. Heaton

Making rear contact. Triangulation party of E. O. Heaton

Measuring the base - note police protection. Triangulation party of E. O. Heaton

Base line measurement - maintaining proper tension on the tape.

Lining stakes in on the Ranchester Base. Triangulation party of Herman Odessey

Measuring over stands on the Inman Base. Triangulation party of E. O. Heaton

Traverse party at Station Turn. Area flooded after August 13, 1928 hurricane. Party off of HYDROGRAPHER

Traverse party in the Everglades. Forward measurement party. Party off of HYDROGRAPHER

Taking measurement while tension being maintained.

Base line measurement party. Triangulation party of Carl Aslakson

Taping across intersection. St. Nicholas and Amsterdam Avenue. Note police protection

Taping party protected from traffic by police

Carcross Base. Alcan Highway geodetic control work. Triangulation party of John Bowie

First C&GS electronic base line measurements. Base crossings by aircraft and ship over Shoran network. Minimum value from two range-range stations gives distance. Base line party of P. C. Doran

First C&GS electronic base line measurements. Base crossings by ship over Shoran network. Minimum value from two range-range stations gives distance. C&GS Ship EXPLORER

First Tellurometer traverse by C&GS. Atka Island traverse. Party off of EXPLORER

Tellurometer traverse in Alaska

Tellurometer traverse at Columbia Glacier

Tellurometer traverse somewhere cold and miserable. Note clouds below station

Electro-chain measurements at Sawmill Bay.