Station Greene, Indiana. Instrument height is 152 feet above ground. 39th Parallel Survey. Triangulation party of George A. Fairfield

Great Caspar Signal - built around tree trunk. Note boatswain chair transporting man to top. 135-foot signal --- main wood scaffold supports instrument. Tree trunk supports small scaffolding and observer at top. Western terminus of 39th Parallel Survey

Wooden signal being built in Alaska.

Jasper Bilby setting up 60' reconnaissance pole. At Station Elbow - connecting with 98th Meridian Survey

John F. Hayford observing from 60' reconnaissance pole. On 98th Meridian Survey. Checking for intervisibility between stations. Helping plan for necessary height of tower at station

Jasper S. Bilby observing from short reconnaissance pole attached to tree. On 98th Meridian Survey. Checking for intervisibility between stations. Helping plan for necessary height of tower at station

Jasper S. Bilby observing from reconnaissance pole attached to tree. Top of pole is 104 feet above ground. Checking for intervisibility between stations. Helping plan for necessary height of tower at station

Beginning to erect tower at Station Hugo. Lines snapped dropping pole seconds after picture. Triangulation party of William H. Burger

Raising one side of instrument tripod at Station Hugo. Triangulation party of William H. Burger

Raising third leg of instrument tripod at Station Hugo. Triangulation party of William H. Burger

Framing first and third leg of instrument tripod at Station Hugo. Triangulation party of William H. Burger

Completed instrument tripod at Station Foss. Photo #1 of sequence

First side of observer scaffolding being raised at Station Foss. Photo #2 of sequence

Both sides of observer scaffolding in place at Station Foss. Photo #3 of sequence

Putting ties on scaffolding at Station Foss. Photo #4 of sequence

Completed tower with internal instrument tripod at Station Foss. This station took 1 and 1/2 days to complete. Photo #5 of sequence

Station Pen in Washington. Triangulation party of O. B. French - occupied by J. S. Hill. Instrument was mounted on tree trunk. Instrument remained steady in azimuth but unsteady in level

Station Gibuson - a 68 foot tree signal. Party of John F. Pratt - off of PATHFINDER

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