John Fillmore Hayford
John Fillmore Hayford (born May 19, 1868 in Rouses Point, New York, † March 10, 1925 in Evanston, Illinois) was an American engineer and geodesist , best known for his 1909 " Hayford ellipsoid " .
Hayford was the first to take into account the mass distribution in the interior of the earth when determining the exact shape of the earth - namely the hypothesis of isostasis down to a depth of about 100 km. However, the continents only fulfill this swimming equilibrium to about 90 percent, so that Hayford's data on the earth's axes deviate by about 300 m from the modern values despite the good methodology. This corresponds to 0.04 per thousand of the earth's radius , which had never been achieved before and was 3 times more precise than the then prevailing Bessel ellipsoid .
The International Union for Geodesy and Geophysics (IUGG) adopted Hayford's results as the International Ellipsoid 1924 at its 1924 congress . However, since somewhat better international ellipsoids were established in 1967 and 1981 , the term “Hayford ellipsoid” has mostly been used since then.
In 1911, Hayford was elected to the National Academy of Sciences . Since 1915 he was a member of the American Philosophical Society . A crater on the moon was named after Hayford .
Web links
- Biographical Memoir (PDF file; 5.78 MB)
Individual evidence
- ^ Member History: John F. Hayford. American Philosophical Society, accessed September 25, 2018 .
| personal data | |
|---|---|
| SURNAME | Hayford, John Fillmore |
| BRIEF DESCRIPTION | American engineer and geodesist |
| DATE OF BIRTH | May 19, 1868 |
| PLACE OF BIRTH | Rouses Point, New York |
| DATE OF DEATH | March 10, 1925 |
| Place of death | Evanston, Illinois |