Ferrel, Wm
Ferrel, William.
ACHIEVEMENT(S): Ferrel’s Law (founding geophysics)
NICKNAME/ALIAS:
DATE/PLACE OF BIRTH: 29th January 1817, in Fulton County, PA.
DATE/PLACE/AGE AT DEATH: 18th September 1891, in Maywood, KS. Aged 74.
DISCIPLINE: Geophysics.
FIELD: Meteorology.
LANGUAGE: English.
PARENTS: Benjamin Ferrel and a Miss Miller.
SIBLINGS: Jacob.
SPOUSE: None.
CHILDREN: None.
EDUCATION: Common school. Marshall College, Mercersburg, Pennsylvania.
Bethany College, Bethany, Pennsylvania.
MAJOR WORK: Ferrel’s Law
LIFE AND TIMES: In his early years, while Ferrel was working on the family farm, he read about mathematics, mathematical physics and surveying whenever he could. The experience of seeing a partial solar eclipse in 1832 got him interested in celestial phenomena and he taught himself how to predict solar eclipses.
In 1844, he moved to Liberty, MO, where he was a teacher for six years before moving to Allensville, KY, where he published his first scientific paper in Benjamin Anthrop Gould’s ‘Astronomical Journal’. This was a work on tidal friction, which he wrote after studying Newton’s* ‘Principia,’ and Laplace’s* ‘Méchanique Céleste,’ and in which he questioned Laplace’s theories on the minimal effect of tides on slowing down the rate of the Earth’s rotation.
Theories about the Earth’s rotation were popular with scientists during the first half of the nineteenth century and Ferrel followed all of the current ideas, particularly those of Coffin and Buys-Ballot*, who had both discovered that winds travel along paths of constant pressure. In 1851, Foucault* had also shown the displacement effect of the Earth’s rotation.
Ferrel made his next important contribution to the field in 1856, with ‘Essay on the Winds and Currents of the Ocean’, in the Nashville Journal of Medicine and Surgery. Influenced by Maury’s* book ‘Physical Geography of the Sea,’ published a year earlier, Ferrel argued that the movement of wind and water along lines of constant pressure was caused by the Earth's rotation.
Between 1858 and 1861, he proved this theory mathematically, arriving at a conclusion known as Ferrel’s Law, which stated ‘if a body is moving in any direction, there is a force arising from the Earth’s rotation which always deflects it to the right in the northern hemisphere and to the left in the southern.’ This statement, in effect, founded modern geophysics.
The American Ephemeris and Nautical Almanac, an annual publication of the United States’ Nautical Almanac Office, gave Ferrel his first scientific work, and in 1858 he moved to Cambridge, MA, to be nearer the job. This move brought the added advantage of close contact with the library at Harvard University, as well as giving Ferrel the chance to develop a friendship with Benjamin Pierce, the mathematician.
In 1864, Ferrel returned to the problems of tidal theory in a paper he read to the American Academy of Arts and Sciences. This paper produced the first quantitative treatment of tidal friction, confirming his claim that the action of the moon and sun on the tides must have the effect of slowing down the rotation of the earth.
Ferrel moved to Washington, DC, in 1867, to join the United States Coast Survey, at the invitation of Pierce, who was now its director.
In 1876, the British physicist Kelvin* designed a tide predictor and in 1880 Ferrel produced his more compact version, which gave maximum and minimum data, rather than a continuous curve. Ferrel’s machine went into operation in 1883 and was used for more than a quarter of a century. As one of the earliest examples of large-scale computing machinery, Ferrel’s tide predictor was an important step in the introduction of machines to perform complex calculations.
Between 1882 and 1886 he worked at the United States Army Signal Service, the predecessor of the Weather Bureau and, soon after, he retired to Kansas, where his brother lived with his family.
Finding Kansas devoid of scientific associates and good libraries, he went east again for a few years, returning eventually to Kansas where he died.
ASSESSMENT: His name is preserved in the meteorological term Ferrel Cell, identifying a segment of the wind circulation model of the Earth.
EXTRA CONNECTIONS: His work is linked with that of Humboldt* and Coriolis*
ONELINER: William Ferrel, founder of geophysics
BIBLIOGRAPHY:
ANB