Workers drawing electrical plan, Cambridge, 1950
Three Japanese acoustic locators mounted on four-wheel carriages, being inspected by Japanese Emperor Shōwa. Before the invention of radar, elaborate listening devices called "War Tubas" were developed to detect the approach of enemy aircraft.
Map showing passenger traffic on Frankfurt streetcar lines, 1913. Strips of wood are glued above each street having a transit line. Each strip represents 4,000 passengers.
Statistical exhibits on parade, New York, 1913. Large charts are mounted on wagons and viewable from both sides of the street.
Suffragettes marching down Fifth Avenue, 1917. (why are all their signs blank?)
Sidewalk widths in the event of an evacuation, 1925.
Friedrich Hess, Model of a Schematic Laser Position, 1942.
Alexander Graham Bell's tetrahedral kites, 1908
The Human Liberty Bell; 25,000 officers and men at Camp Dix, New Jersey, ca. 1918.
Luncheon seating arrangement, 1911
Seating chart, State of the Union address, 1914