The Office of the Chief Signal Officer sent these letters discussing reporting errors, budgetary issues, personnel reassignments, and changes in procedures to its observers in Knoxville, Tennessee during the 1870s and 1880s. Sergeant John K. Payne served as observer until December 31, 1879, when he was replaced by Private B. F. Hough.

The majority of the letters in this collection were sent to Payne, the Signal Service's Observer in Knoxville from the department's headquarters in Washington, D.C. between January 8, 1874 and December 19, 1876. Most of the letters discuss errors in Payne's reports, budgetary issues, personnel reassignments, and changes in recording and reporting procedures. Many of the documents are signed by H. W. Howgate (Acting Signal Officer and Assistant) and H. Jackson (Property and Disbursing Officer). A few of the letters are addressed to Payne's assistant, Private Ignatius V. Wallace, who was assigned to the station in August 1874.

This collection also houses official letters that the Signal Service sent to Private B. F. Hough, who replaced Payne in January 1880, between January 8 and December 21 of 1880. Like the correspondence addressed to Payne, these letters detail errors in Hough's reporting and discuss budgetary matters.