Historical Markers
Allegheny Observatory Historical Marker
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Allegheny Observatory

Pittsburgh Region


Marker Location:
Riverview Ave. in Riverview Park (off U.S. 19) near Observatory, Pittsburgh

Dedication Date:
November 2, 1999

Behind the Marker

Exterior of the Original Allegheny Observatory, 1900.
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The University of Pittsburgh's Allegheny Observatory, circa 1912.
In 1896, seven years before the Wright brothers flew over the sand dunes of North Carolina and into history, Samuel Pierpont Langley launched a steam-powered airplane above the Potomac River and watched it fly more than half a mile. Alexander Graham Bell, America's celebrated inventor of the telephone, would later write that "No one has contributed more to the modern revival of interest in flying machines of the heavier-than-air type than our own Professor Langley."

Langley began his research into flight at the Allegheny Observatory, an institution that began humbly in 1859 when twenty amateur astronomy buffs formed the Allegheny Telescope Association and pledged $100 each to purchase a telescope for the City of Allegheny, now Pittsburgh's "North Side" neighborhood.
On the Steps of the Allegheny Observatory: John Stanley Plaskett (Back left), William Snyder Eichelberger, Frank C. Jordan, Frank Schlesinger, Edward C. Pickering (Standing in the Center), John A. Brashear (to the Right of Pickering), William Thaw (Seated Left of Pickering) and Daniels.
Allegheny Observatory luminaries, photographed on the observatory's steps, Pittsburgh,...
The Association soon erected a building near Perrysville Avenue and in 1861 installed an impressive 13-inch refracting telescope, which at that time boasted the third-largest lens in the world. The Civil War, however, diverted the interest of its incorporators, and by 1867 the building and telescope had merged with the Western University of Pennsylvania (now the University of Pittsburgh), which hired Langley as the observatory's first professional director and as a professor of Astronomy and Physics. Trained as a civil engineer, Langley had worked at the Harvard Observatory and taught mathematics at the U.S. Naval Academy in Annapolis, Maryland, before accepting the position in Pittsburgh. There, he found little of use besides the telescope.

Securing new equipment through the observatory's chairman, William Thaw, a manager of the Pennsylvania Railroad, Langley guided the observatory toward scientific study, particularly sunspots, and acquired a small transit telescope, which used the position of stars to tell time. In 1869, Langley devised a system to transmit time signals via telegraph–a service that enabled railroads to synchronize schedules between towns, none of which otherwise coordinated their timekeeping. With the subscription of the Pennsylvania Railroad and other Pittsburgh firms, the observatory was soon earning some $3,500 annually, which helped fund further research.
This image shows the   the aerodrome landing in the water.
Catapulting of the Langley aerodrome from a specially constructed houseboat...

Influenced by an Observatory assistant's fascination with nature, Langley began to study birds' wings in relation to flight. In 1887, he devised a "whirling table" made of two thirty-foot-long wooden arms that could spin surfaces at different speeds and angles eight feet above the ground around a vertical axle. That same year, Langley became assistant secretary of the Smithsonian Institution in Washington, D.C.

After the death of the Smithsonian's secretary led to his promotion to that position in November, Langley spent increasingly more time in Washington, D.C. Back in Pittsburgh, his assistant continued aerodynamic experiments on flat surfaces. Curiously, Langley did not study the aerodynamic properties of curved surfaces, or airfoils, which the Wright Brothers would soon use with great success. He did, however, use findings from his whirling table to argue that the amount of power necessary to push a plane through the air diminished as its speed increased. Langley's Law, as it became known, convinced many early aeronautical pioneers that flight was only possible at high speeds. (Later experiments would prove Langley's assumption to be wrong.)
Samuel Pierpont Langley (1834-1906) and Charles M. Manly (left), chief mechanic and pilot on board the houseboat that served to launch Langley's Aerodrome aircraft over the Potomac River
Samuel Langley (right) with pilot and chief mechanic and volunteer pilot Charles...

By 1887, Langley was also building airplane models or "aerodromes" in Pittsburgh, but of the dozens he tried, none flew more than eight seconds or traveled more than 100 feet. After resigning as observatory director and moving permanently to Washington in 1891, Langley began to build models that applied the principles learned on his whirling table. As the models grew bigger, the power source changed from rubber bands to steam engines. He consulted with French aviation pioneer Octave Chanute, and began corresponding with Alexander Graham Bell, who was convinced that the future of flight lay with tetrahedral units, a structure made from small triangular shapes that fit together like a box kite.

In May 1896, Langley's unmanned Aerodrome No. 5 twice flew above the Potomac River for more than half a mile, making it the first sustained, mechanically powered flight. Later that year, No. 6 stayed aloft nearly two minutes and traveled 4,200 feet. Lacking any system for control, the models were of little practical use. Langley, however, was satisfied with the results and gave up his experiments until tempted back into the field by President McKinley and the U.S. War Department, which offered funding for the development of a manned airplane.
A man seated in a chair, wearing a suit.
Samuel Pierpont Langley, director of the Allegheny Observatory from 1867 to...
Perhaps, too, Langley was also motivated by competitive spirit, for Chanute was now corresponding with Wilbur and Orville Wright about their aeronautical experiments. In October and December of 1903, Langley conducted two unsuccessful tests of his first piloted aircraft, the "Aerodrome A," which were observed, marker and late described by Alexander Bell.

Concentrating his interests on how to power a flying machine, Langley had overlooked the importance of stability and control, which others were mastering through manned glider experiments. On December 17, 1903, just over a week after Langley's "intrepid assistant" crashed the Aerodrome A into the Potomac River, the Wright brothers achieved the world's first powered and controlled flight at Kitty Hawk, North Carolina. Langley sent his congratulations, and they, in return, credited his experiments for inspiring their own work.

Samuel Langley died of a stroke on February 27, 1906, just two days after the newly formed Aero Club of America passed a resolution honoring his labors as a pioneer in the "important and complex science" of "Aerial Locomotion." Bell blamed Langley's death on the American press's derisive and nasty coverage of Langley's failed attempts at flight, which Bell believed had "broke his heart." His name is perpetuated by Langley Air Force Base outside of Washington, D.C.

After Langley's departure, the Allegheny Observatory continued to make advances in the field of astronomy. In 1912, it moved to a new building with a thirty-inch refracting telescope, constructed bymarker John A. Brashear, which is still used to study the distances to nearby stars.
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