Tower at Station Indian covered with ice and frost. Station is just below the Arctic Circle. Triangulation party of Walter R. Helm

Small wooden stand on ridge in Mojave Desert. Station built during observations on Transcontinental Traverse work. Triangulation party of Woodrow Johnson

Early steel gas pipe tower built by the Lake Survey.

The first picture of a Bilby portable steel tower under construction. Bilby towers were made of prefabricated steel parts that could be reused. These towers were designed by Jasper Bilby, chief signalman of the C&GS

The first picture of a completed Bilby tower. Bilby towers were made of prefabricated steel parts that could be reused. These towers were designed by Jasper Bilby, chief signalman of the C&GS

Using Bilby towers for hydrographic signal on the Florida coast. Built by party off of HYDROGRAPHER

Bonita tower in southwest Florida. Traverse party measuring distance in foreground. Party off of HYDROGRAPHER

A 90-foot tower wrecked by a storm. Triangulation party of Earl O. Heaton

Tower at Station Schnackenburg.

Building Station Reid. Triangulation party of Paul A. Smith

Power source for hoisting steel. Jack up truck and use "fifth wheel". This could be dangerous - at least one leg broken by getting wrapped up. Safety modifications made to system after individual severely injured. Triangulation party of Paul A. Smith

Preparing to dismantle Station Village Mills South Base. Triangulation party of Paul A. Smith

Climbing the tower at Station Walting. On the Ohio-Indiana boundary. Triangulation party of H. C. Warwick

Straightening steel - even the portable towers needed some maintenance. Triangulation party of C. D. Meaney

A study in geometry - looking up a Bilby tower. Station South Bend, Louisiana. Triangulation Party of Eugene R. McCarthy

50-foot Bilby tower in Nebraska or Montana. Triangulation party of Wilbur Porter

Looking down from the top of a 50-foot tower. Triangulation party of Wilbur Porter

Looking up the side of a 50-foot tower. Triangulation party of Wilbur Porter

Tower with observing tent to shield the instrument from the wind. Triangulation party of Wilbur Porter

Tower at Station Bowie.

Collimating the inner tower at Station Winnie. Collimation involved placing the observing instrument directly over the mark. Triangulation party of Carl I. Aslakson

Lightkeeper orienting lights for distant observers. Tower at Station Northome. Osborne at lights, Caouette recording, Tryon at tent. Triangulation party of Carl I. Aslakson

Tower at Station Eufaula.

Tower at Station Northome. Caouette on left, Osborn on right, Tryon observing. Triangulation party of Carl I. Aslakson

Tower at Station Winnie next to firetower. Triangulation party of Carl I. Aslakson

Photos # 5-7 show stages in completing a 50-foot tower at Station Tatum. Photo #8 shows theodolite being transported to top of tower. Triangulation party of Wilbur Porter. Photos # 5-8 of sequence

Station Weingard near Amarillo. Triangulation party of Wilbur Porter

Photos #1-4 show beginning of construction of 50-foot tower at Station Tatum. Triangulation party of Wilbur Porter. Photos 1-4 of sequence

Observing party on 103-foot tower in Missouri. Triangulation party of Carl I. Aslakson

Station Hunter - 159 feet - one of the bigger towers. Photo #2 of sequence. Triangulation party of Kenneth Crosby

A 159-foot tower. Note men on top and man climbing up

Building the tower at Station Hunter. Photo #1 of sequence. Triangulation party of Kenneth Crosby

Tower at Loma Prieta, Santa Cruz Mountains, covered with ice. Triangulation party of Lorne G. Taylor

Tower built with native timber.

Bilby tower built on oil rig south of New Orleans.

Tower at Station Whitsett destroyed by wind. Triangulation party of E. O. Heaton

A rough ride down. Drove his head right into the ground. Photo #1 of sequence

Ah, we're O.K. Just kidding! Photo #2 of sequence

A tower with a bad day. Anchor boards pulled out

Another tower with a bad day. Standing at the top (or what was the top)

A 90-foot tower wrecked by a storm. Triangulation party of E. O. Heaton

Looking through the twisted steel of a 90-foot tower wrecked by a storm. Triangulation party of E. O. Heaton

Tower blown down during September 1933 hurricane. Triangulation party of Roland D. Horne

Station Post on a good day. Triangulation party of Kenneth G. Crosby. Triangulation party of Kenneth G. Crosby

Station Post emulating the "Leaning Tower of Pisa". Leg settled badly in vicinity of ditch. Tower was rebuilt with one leg placed in center of road

Bilby tower failure at Station Flatlick due to tornado. Triangulation party of E. L. Jones

Bilby tower failure at Station Flatlick due to tornado. Triangulation party of E. L. Jones

Ferdinand Hassler's camp at the west end of the Great Fire Island Base Line.

George Davidson camp near the San Lorenzo River.

Breaking camp on Uncompahgre Peak - over 14,000 feet elevation. During the 39th Parallel Survey. Triangulation party of William Eimbeck