Showing light on the meridional arc between Anchorage and Fairbanks. Triangulation party of William Scaife.

Lightkeeper preparing to pack into station in Alaska. Often the lightkeepers would be on their own for weeks at a time in the wilderness while waiting for completion of triangulation observations.

Signal building for triangulation work on the Alaska coast.

Signal building for triangulation work on the Alaska coast.

A lightkeeper with his trusty pack dogs on the way to a station during triangulation operations in central Alaska.

Lightkeeper standing at the top of a tower constructed of timber cut on the spot in central Alaska.

A wooden triangulation tower within a tower. Inner tower was to support the instrument while the outer tower supported the observer.

A tough climb for an observing party in central Alaska.

Theodolite used for observations in central Alaska.

Stopping on the trail for lunch on the way to a triangulation station in central Alaska.

Oscar Risvold after a season in the Alaskan wilderness on triangulation work.

Bill Scaife mushing his way to a triangulation station.

A tractor carrying fuel in central Alaska.

Unidentified river in Alaska.

Alaska coastal scene.

Railroad in the interior of Alaska.

Triangulation crew used velocipedes when on the Anchorage to Fairbanks railway prior to heading into the wilderness for triangulation work. Triangulation party of William Scaife.

Leaving the velocipede and getting ready to head into the wilderness along the Alaska to Fairbanks railway. Triangulation party of William Scaife.

The building crew at a triangulation tower in central Alaska. Triangulation party of William Scaife.

Members of triangulation crew of William Scaife in the interior of Alaska on a velocipede between Anchorage and Fairbanks.

A gasoline powered velocipede underway near a railroad siding on the Anchorage to Fairbanks railway.

Packing into the interior. Stopped at a food cache. Triangulation party of William Scaife.

Letting the horses stop to graze on the way into the interior. Believe Mrs. William Scaife is in right center of picture. North of Anchorage.

Crossing over one of the many rivers in central Alaska on a suspension bridge. Triangulation party of William Scaife

Crossing over one of the many rivers in central Alaska on a suspension bridge. Triangulation party of William Scaife

Reconnaissance photo of the Salmon River country as taken from cooperating Army Air Forces aircraft.

Reconnaissance photo of the Salmon River country as taken from cooperating Army Air Forces aircraft.

A look into the canyon of the Salmon River from above.

Starting into the River of No Return Wilderness along the Salmon River. There was packing trouble to start with.

Loading the pack horses at our camp on Cash Bar on the Salmon River.

Floyd Risvold's pack train leaving Dale Ranch, about half way to the next camp.

The two pack trains leaving Cash Bar. Lew Odgers was in the lead and Floyd Risvold was on the white horse, the last on the left. Each pack train had a "belle mare" that was always in the lead.

Lew Odgers' pack train lined up as though ready to hit the trail! This was at Floyd Risvold's camp at the mouth of the Wind River.

Makeshift boat used by level crew of Ira Rubottom along the Salmon River. Definitely a one-way trip.

Makeshift boat used by level crew of Ira Rubottom along the Salmon River. Definitely a one-way trip.

Makeshift boat used by level crew of Ira Rubottom along the Salmon River. Definitely a one-way trip.

Makeshift boat used by level crew of Ira Rubottom along the Salmon River. Definitely a one-way trip.

Makeshift boat used by level crew of Ira Rubottom along the Salmon River. Definitely a one-way trip.

Floyd Risvold, Lew Odgers, Johnny, and James Beck, Jr. The last three were the two packers and horse wranglers.

Lt. Charles Pierce in the lead with Cowboy Roy Bixby in the rear. Horse-packing into a station in the Big Sur country south of Monterey.

Lt. Bill Tucker and Jack Marks fail to erect observing tent in heavy winds on Pt. Sur.

Floyd Risvold with theodolite on top of old brewery near the Navy destroyer piers.

Looking north up the Big Sur coastline from Station Waters on Partington Ridge.

Building an observing stand at Station Waters.

A view of Station Waters.

Floyd Risvold standing on top of 110-foot tower with Bill Kessler climbing up the ladder leg at Station Livingston. Where Risvold is standing is not much more than a foot to foot and a half wide and nothing but air to hang on to. Party of Lt. John Bowie.

Floyd Risvold sitting on cross-member of Bilby Tower approximately 100 feet up. Party of Lt. John Bowie.

Looking up to the top of a 110-foot Bilby Tower with Bill Kessler on the way up.

Walt Howard fishing at base of Tower Falls, Yellowstone National Park.

Floyd Risvold fishing at brink of Tower Falls, Yellowstone National Park.