White River West Base on the 141st Meridian Survey. International Boundary Commission surveyors

Rock cairn signal at divide between two main forks of the Ladue River. International Boundary Commission surveyor

Platform and stand built between two trees on Olympic Peninsula. Note man standing on platform. Triangulation party of H. A. Seran

The crow's nest at Station Moclips - 215 feet above the ground. Note spikes driven into tree - builders would drive spikes and go hand over hand . Triangulation party of H. A. Seran. According to Seran: "It took men of uncommon nerve to do this work."

239-foot tower built on Bugsuk Island in southwest Philippines. This tower was built completely from native timber cut on location. It took 19 men off the PATHFINDER three weeks to build this signal. This was the largest wooden tower ever built by the C&GS. Used for both observing and as a signal

Wind tarps draping tower at Station Bippus. Wind tarps protect inner instrument tower from wind. Triangulation party of Earl O. Heaton

Removing wind tarps at Station Umbarger. Wind tarps protect inner instrument tower from wind. Triangulation party of Earl O. Heaton

100-foot tower at Bozeman NW Base. Note man at top. Triangulation party of William M. Scaife

115-foot tower built around tree on Sarangani Island.

Tower at Station Mangal. Topographic party working on the beach

Tower with signal flag at Station Bint. At Bihintinusa Island off the south coast of Basilan. Built by crew off the MARINDUQUE

Station Mangal from offshore. Built by crew off the MARINDUQUE

Building crew after finishing the tower. Party off the MARINDUQUE

Building a tower. Party off the MARINDUQUE

The finished tower - note guard in lower left of tower. Party off the MARINDUQUE

A finished large tripod signal - note the guards. Party off the MARINDUQUE

115-foot tower built around tree on Sarangani Island.

Another view of tower built around a tree on Sarangani Island

Small tower on a coral islet

Tower with signal

239-foot tower built on Bugsuk Island in southwest Philippines. This tower was built completely from native timber cut on location. It took 19 men off the PATHFINDER three weeks to build this signal. This was the largest wooden tower ever built by the C&GS. Used for both observing and as a signal

Using a day marker as a tower. Photo#1 of sequence

Observing angles from the top of the day marker. Photo#2 of sequence

Tower built around tree in the Philippine jungle.

Triangulation station built in shoal water. Combined operations party of Hubert A. Paton

Tower built around a tree trunk.

Station Plainview in eastern Montana. Triangulation party of Wilbur Porter

Station Cook - tower had to be built after error by reconnaissance man. Triangulation party of Wilbur Porter

Hecht was the observer at this station in North Dakota. Small wooden observing stand. Triangulation party of Wilbur Porter

103-foot light stand at Station Red Cloud.

Climbing a small tower at Station Pinnacle. Providing horizontal control survey for aerial photography of King County

Pole tower built from native timber at Takhini West Base. Note signal flag on tree. Triangulation party of F. B. Quinn

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