Lieutenant B. H. Riggs tending tide gage during MacMillan Arctic Expedition on Schooner BOWDOIN.

Installing tide staff during MacMillan Arctic Expedition on Schooner BOWDOIN.

Checking a water level gauge.

Portable tide gauge.

Standard automatic tide gauge.

Establishing a field portable automatic tide gauge.

Checking a tide gauge.

Tide gauge installation at Cape Mordvinof.

Portable tide gauge mounted on float well showing float.

Coast and Geodetic Survey tide house.

Recording device in tide house. Possibly tides registering somewhere in western Gulf of Mexico.

Coast and Geodetic Survey tide prediction machine in use in WWII with woman operator.

Jim Dixon running the gun checking the stability of the tide staff in Boston Harbor to determine if ice has affected the stability of the staff.

Recording device for standard tide gauge.

Haskell water level gauge.

Station Burnt Point. U.S. Lake Survey Signal as remodeled after Canadian Signal done with. See image cgs00701.

Observing section along Section Drydock on the St. Clair River.

Lake Survey field party camp.

Observing tower at Station Detour. This wooden tower was erected in 1893 and removed in 1903 and replaced by a gas pipe observing tower.

Observing tower at Fort St. Joe.

Station Hayes. A 22-foot observing stand built of green Norway spruce and dry Cedar.

Gas pipe tower erection. Building a 9-foot inside tower section on tower over Station Detour.

Building an 18-foot outside section of a gas pipe tower at Station Detour.

Camp No. 7. Construction camp lived in during building of observing tower for Station Comstock.

Either cleaning up or in need of a new cook. This camp, Camp No. 6, was a one- night stop.

Temporary camp on Great Duck Island.

Tower erection camp at Station Duck on Great Duck Island.

Heliotrope and observing instrument at Station Gatacre (secondary triangulation. ) Heliotrope on four foot tripod.

"Simpson and his perch." Scaffold for heliotrope at Station Stoville. 35 feet to top of cutoff maple tree. Station built in 6 hours.

Screwing in a big leg on a gas pipe observing tower on Station Walker.

"Entering a big leg" on a gas pipe observing tower at Station Duck.

Observing stand at Beavertail Point, first erected in 1851. Used on secondary triangulation.

Station Reid, a 25-foot observing platform.

Station Greenbush, a 44-foot observing tower that was blown down a few months after being built.

A 36 foot observing tower at Station Stovel.

Level party running a section of the Niagara River between Ashland Avenue Gauge Station and the head of the Whirlpool Rapids. A levelman, recorder, rodman, and anchorman were working in 20 below zero Fahrenheit temperature. Rodman Richard Sides and anchor-man Roy Stack are shown in picture.

Twelve-foot observing stand with 30-foot signal at Station Phillips Hill.

Sixteen-foot observing stand at Station Reid.

Station Burnt Point. Canadian Signal. See image cgs00678.

Water level gage on Section Gorge.

U.S. Lake Survey water level gauge.

U.S. Lake Survey water level gauge.

Lake Survey employee Jim Morris checking water level gauge.

Lake Survey water gauge house showing water level for mariners.

Haskell current meter Type B.

Haskell current meter Type A. Foreshortened view.

Haskell current meter Type A. Foreshortened view.

Lake Survey employee Jim Morris checking water level gauge.

U.S. Lake Survey camp at Bayfield, Wisconsin.

U.S. Geological Survey electrical type water level gauge.