Designed by William A. Truesdell, a railroad engineer, the Seventh Street Improvement Arches celebrates the engineering application of mathematics to improve living conditions.
Three rivers - the Allegheny, Monongahela, and Ohio - join in Pittsburgh, making the city a natural site for the building of bridges. But the Smithfield Street Bridge stands apart from other Pittsburgh bridges for several reasons: it replaced structures by two well-known bridge engineers, Lewis Wernwag and John A. Roebling; it was the first use in America of the lenticular - or lens-shaped - truss design; and it was one of the first major bridges in the U.S. built primarily with steel.
The glider was the first heavier-than-air human-carrying aircraft to achieve controlled piloted flight. On his first successful flight, August 28, 1883, John Montgomery soared at about 600 feet. The Montgomery glider's success demonstrated aerodynamic principles and designs fundamental to the modern aircraft.
The Fresno scraper established the basis for the modern earthmoving scraper, being able to scrape and move a load of soil, then discharge it at a controlled depth. It quadrupled the productivity of manual labor, replacing hand shoveling of earth into horse carts.
On May 24, 1883, with schools and businesses closed for the occasion, New York celebrated the opening of the Brooklyn Bridge. Also known as the Great East River Bridge, it was built over 14 years in the face of enormous difficulties. Deaths, fire in the Brooklyn caisson, and a scandal over inferior materials all added to the turmoil. The bridge is one of the most well-recognized symbols of American engineering, and remains the unofficial Eighth Wonder of the World.