Spirit Leveling, 1905
By Land Subsidence in California
1905 (approx.)
![Black & white photo of two USGS scientists conducting spirit leveling in the field](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/spirit-leveling.png?itok=BXzEKfnw)
Detailed Description
USGS survey party spirit leveling near Colusa, Sacramento Valley, circa 1905. Photo by John Ryan, donated courtesy of Thomas E. Ryan.
Sources/Usage
Public Domain.