Paragon adjustable and reversible aircraft propeller created by Spencer Heath and tested on October 11, 1922, Bolling Field, Washington, D.C.

Founded in 1917 as The Flying Field at Anacostia, the Bolling Field was the first military airfield near the United States Capitol. It was renamed Anacostia Experimental Flying Field in June 1918. Throughout the Second World War, Bolling Field served as the aerial gateway to the US capital Washington D.C. After WWII, Bolling Field's property became Naval Air Station Anacostia and a new Air Force base, named Bolling Air Force Base, was constructed just to the south of the field in 1948.

The Harris & Ewing, Inc. Collection of photographic negatives includes glass and film negatives taken by Harris & Ewing, Inc., which provide excellent coverage of Washington people, events, and architecture, during the period 1905-1945. Harris & Ewing, Inc., gave its collection of negatives to the Library in 1955. The Library retained about 50,000 news photographs and 20,000 studio portraits of notable people. Approximately 28,000 negatives have been processed and are available online. (About 42,000 negatives still need to be indexed.)