This engraved printing plate was prepared to print an image of "Diagram of a Triangulation of the Yiti Group or Feejee Islands by the U.S. Ex. Ex." for the publication "United States Exploring Expedition, During the Years 1838, 1839, 1840, 1841, 1842," Volume 23, Hydrography, preceding page 7, in the edition Philadelphia : C. Sherman , 1861. The engraving was prepared by W. H. Dougal.