| Added by |
 Alain Martineau
|
| General Description : | Samuel P. Langley almost developed a heavier-than-air flying machine, but it crashed into the Potomac. With no more than a high school education, Langley learned by studying and experimenting. His principal interest was astronomy. After the Civil War, he was given an assistantship at the Harvard Observatory. He then taught mathematics at the U.S. Naval Academy, and for 20 years he was professor of physics and astronomy at what now is the University of Pittsburgh and director of the Allegheny Observatory. Langley invented the bolometer in 1878, an instrument that detects and measures minute amounts of radiant energy. In 1887 he moved to Washington, DC, to be secretary of the Smithsonian Institution, where he established the Astrophysical Observatory and the National Zoological Park. |
| Face value | 45 US cents |
| Catalog code (Michel) | US 1977 |
| Series | Aviation Pioneers |
| Stamp colour | multicolor |
| Stamp use | Airmail stamp |
| Issue date | 14/05/1988 |
| Print technique | Lithographed and Engraved |
| Perforation | 11 |
| Height | 25.00 mm |
| Width | 40.00 mm |
| Catalog prices | No catalog prices set yet |
