Heartsill's hand drawn map of Camp Butler, Union camp for Confederate prisoners, near Springfield Illinois, c. 1861-1865

Journal describes Heartsill's experiences during the U.S. Civil War, including material related to Texas ranching activities, Indian and Mexican affairs, and botany; the Texas Secession Convention; generals Braxton Bragg, Stonewall Jackson, Joseph E. Johnston, and John W. Whitfield; his work with the W.P. Lane Rangers (later Company F, 2nd Regiment, Texas Calvary); battles of Chickamauga and Vicksburg; prisoners of war; and Confederate Army Trans-Mississippi Department.

Heartsill wrote the journal on the scene in small notebooks that he kept in his pocket. These notebooks were sent to back Texas from the front as he filled them up. The journal draft located here at Rice University journal is one of two surviving drafts in Heartsill's hand. The other draft is located at the University of Texas at Austin. These drafts indicate that Heartsill made some attempt to correct spelling and grammatical errors before printing the journal. After the war, Heartsill printed one hundred copies of the journal himself on an "Octavo Novelty Press", over the time period of December 9, 1874-July 1, 1876. The provenance of this journal makes it unique in the field of U.S. Civil War soldier narratives.