1916. "Brick yard below Mount Vernon." Harris & Ewing. View full size.

1917. "Baltimore and Ohio Railway. Safety first train." The train, according to newspaper accounts, carried exhibits "informing the public of the careful and effective means that are being taken by the government in the interest of good health, safety and preparedness." Shown here at Union Station in Washington. Harris & Ewing Collection glass negative. View full size.

1915. "National Guard of D.C. -- Field tactics." Nothing like a blanket toss to confuse the enemy. Note the Hollywood type behind the movie camera. Harris & Ewing Collection glass negative, Library of Congress. View full size.

September 1916. "Kron Prinz Wilhelm, German ship, interned in U.S. in tow." The former passenger liner, pressed into service as a commerce raider by the Imperial German Navy at the start of World War I, being towed from the Norfolk yards to Philadelphia. During its eight months on the high seas -- after leaving New York Harbor with 2,000 tons of coal -- the converted 15,000-ton cruiser sank more than a dozen Allied ships and took hundreds of prisoners. Running low on supplies, its crew and prisoners beset by a variety of illnesses, the battered vessel sought refuge in April 1915 at Newport News, where its sailors were interned for over a year. After the United States entered the war, the ship was seized by the government, rechristened the USS Von Steuben and converted into a troop carrier. Harris & Ewing Collection glass negative. View full size.

1916. "Senate pages. Marshall, center, giving dinner to pages." I know you'll all be on your very best behavior. Harris & Ewing Collection negative. View full size.

1917. "Census Bureau, Department of Commerce, tabulating machine." An early punch-card tabulator, a distant forebear of today's computers. Two photos of this monster yet to come. Harris & Ewing Collection glass negative. View full size.

"1916. German sailor interned in U.S." A sailor from the cruiser Prinz Eitel Friedrich, interned along with the Kronprinz Wilhelm, their crews and a menagerie of mascots at Norfolk, Va., in 1915. Harris & Ewing Collection. View full size.