License, verbatimCC0
The Smithsonian Institution: Open Access image dedicated to the public domain under Creative Commons Zero (CC0); usage.access=CC0 on the media record itself.
Dunmore and Critcherson, active 1865-1875. Arctic Regions: Page 33, no. 39, Iceberg with an Arch in It, Which,When Connected with the Glacier, Will Give the Reader to Understand How the Water Flows from the Glacier through these Arches, Causing the Rapid Current, 1869, published 1873. Smithsonian Institution.