Joseph Henry's Letter to George Brinton McClellan (October 18, 1861)

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Letter from Joseph Henry, first Secretary of the Smithsonian Institution, to George Brinton McClellan, General of the Union Army in the Civil War, October 18, 1861. In the letter, Henry informs McClellan of the work of balloonist William H. Helme, a dentist from Rhode Island, and the possible military applications. Henry served as a scientific advisor to President Abraham Lincoln during the war.


  • McClellan, George Brinton 1826-1885
  • Helme, William H c. 1835-1900
  • United States. Army


Historic Images of the Smithsonian


2 pages scanned from the edited transcript of the original version and notes in the Joseph Henry Papers Volume 10, pages 228-229 (Document 123).

Contained within

Rothenberg, Marc, et al, eds., The Papers of Joseph Henry, Volume 10, The Smithsonian Years: January 1858-December 1865 (Smithsonian Institution in association with Science History Publications/USA, 2004), 228-229

Contact information

Institutional History Division, Smithsonian Archives, 600 Maryland Avenue, SW, Washington, D.C. 20024-2520,


  • October 18, 1861
  • Civil War, 1861-1865

Restrictions & Rights

No restrictions


  • Aerial reconnaissance
  • Balloons (Aircraft)
  • Secretaries
  • Letters
  • Aeronautics
  • Dentistry
  • History
  • Ballooning
  • Rhode Island
  • Aerial reconnaissance, American


  • Rhode Island
  • United States


  • Document
  • Paper

ID Number

SIA2012-0038 and SIA2012-0039

Physical description

Number of Images: 2 ; Color: Black and White ; Size: 7w x 10h ; Type of Image: Document ; Medium: Paper

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