A detail from yesterday's post of picnickers at Marshall Hall.

Ornithopter. Hand-colored lithograph c. 1800-1830. View full size. Tissandier Collection, Library of Congress.

"Washington Monument as it stood for 25 years," 1860. Glass-plate (wet collodion) photograph by Mathew Brady. View full size.

1910 Irving Underhill photo of the 22-story Flatiron (Fuller) Building at 175 Fifth Avenue, one of the earliest (1902) buildings in New York to attain such heights. View full size. More here.

Picnic at Marshall Hall, Maryland, 1893. View full size. Photograph by William Cruikshank. View even larger. Across the Potomac River from Mount Vernon, Marshall Hall was a Colonial era estate whose grounds were used for picnics, concerts and camping. The house burned down in 1981. [Note fingerless gloves worn by ladies on the right, and loud suspenders of man on the left. - Dave]

"The Anxious Moment." Poker game at Camp McKibbin, Marshall Hall, Maryland, 1893. With members of the 2nd, 3rd and 6th battalions of the District National Guard. View full size. Photograph by William Cruikshank.

Gen. John F. Hartranft reading the death warrant to the four condemned Lincoln assassination conspirators (Mrs. Surratt, Payne, Herold, Atzerodt) on the scaffold at Fort McNair, Washington. July 7, 1865. View full size. Photograph by Alexander Gardner. More execution photos at GhostCowboy.

Union soldiers on boxcars at railroad depot next to offices of the Atlanta Intelligencer during the city's occupation by General Sherman. View full size. Wet plate glass negative by George Barnard. Alternate view here.

Lewis Payne, seated and manacled, at the Washington Navy Yard about the time of his 21st birthday in April 1865, three months before he was hanged as one of the Lincoln assassination conspirators. View full size. Photograph by Alexander Gardner, probably taken aboard the ironclad U.S.S. Montauk or Saugus.

Three views of Lewis Payne (a.k.a. Lewis Powell) in April 1865, three months before his execution by hanging, wearing the same sweater. View full size. Photographs (wet collodion, glass plate) by Alexander Gardner.

The New York Public Library as seen from the intersection of East 42nd Street and Fifth Avenue. July 14, 1915. Copyright Office Collection. View full size.

Union Army guard at Price, Birch & Co. slave pen at Alexandria, Virginia, circa 1865. Detail of albumen print. View full size. Photograph by Andrew J. Russell.

Exterior view of Price, Birch & Co. slave pen at Alexandria, Virginia, circa 1865. Wet collodion, half of glass plate stereograph pair. View full size.

Interior view showing cells of Price, Birch & Co. slave pen at Alexandria, Virginia, circa 1865. Wet collodion, half of glass plate stereograph pair. View full size.

Price, Birch slave pen cells at Alexandria, Virginia, circa 1865. Wet collodion, half of glass plate stereograph pair. View full size.