Listening Trumpets, 1921

Bolling Field, Washington D.C, USA

A pair of horn amplifiers at Bolling Air Field, Washington DC, USA. Such detectors, developed in response to the rise of military aircraft, were rendered obsolete by the arrival of radar.

Manning the horns is a soldier of the 99th Aero Squadron of the United States Army Air Service who first served in World War 1 on the Western Front, and was re-designated as the 99th Corps Observation Squadron in 1921, coinciding with the unit’s relocation to Bolling Air Force Base in Washington DC. The neo-classical building of the National War College at Fort McNair completed in 1907 in the background of this photograph still exists today.

Original Photograph: National Photo Company Collection
Digital Color Reconstruction: Dynamichrome

This image appears in our upcoming book The Paper Time Machine co-authoured by Wolfgang Wild of @Retronaut and Dynamichrome’s Jordan Lloyd, in collaboration with Getty and @Unbounders.

Find out more about the book and make a pledge at

Original Photograph | Unknown Photographer, gift of Herbert A. French
Format | Glass Negative
Source | Courtesy of the National Photo Company Collection, Library of Congress
Color Reconstruction | Dynamichrome
Words | Wolfgang Wild, Jordan Lloyd

One clap, two clap, three clap, forty?

By clapping more or less, you can signal to us which stories really stand out.