John Michell

John Michell (* December 25, 1724, † April 29, 1793 in Thornhill, Yorkshire ) was an English natural philosopher and geologist.

Michell 1762 Woodwardian Professor of Geology at Queens ' College, Cambridge. In 1760 he was appointed a member of the Royal Society of London.

Michell constructed for the first time a torsion balance to measure the gravitational force, but has not completed by the appropriate examinations. His device was successfully used in 1797, however, after his death by Henry Cavendish to determine the gravitational constant. Cavendish has in his report to the Royal Society specifically to the merits Michell.

Michell is also a co-founder of seismology. 1760 resulted earthquake back to undulations in the ground. He suspected a connection between earthquakes and volcanism.

In 1784 he assumed an influence of gravity on the light. It was not until 1919, three years after Einstein completed the General Theory of Relativity by Arthur Stanley Eddington solar eclipse observation of the diffraction of light was observed experimentally by the gravitation of the sun, could Michell's conjecture are actually confirmed.

Works

  • Observations on the Same Comet. In a Letter to Mr. James Short, FRS In: Philosophical Transactions of the Royal Society. Vol 51, 1759/1760, pp. 466-467, doi: 10.1098/rstl.1759.0044.
  • A Recommendation of Hadley's Quadrant for Surveying, Especially the Surveying of Harbours, Together with a Particular Application of It in Some Cases of Pilotage. In: Philosophical Transactions of the Royal Society. Vol 55, 1765, pp. 70-78, doi: 10.1098/rstl.1765.0010.
  • Proposal of a Method for Measuring Degrees of Longitude upon Parallels of the equator. In: Philosophical Transactions of the Royal Society. Vol 56, 1766, pp. 119-125, doi: 10.1098/rstl.1766.0016.
  • An Inquiry into the probable Parallax, and Magnitude of the Fixed Stars, from the Quantity of Light Which They Afford us, and the Particular Circumstances of Their situation. In: Philosophical Transactions of the Royal Society. Vol 57, 1767, pp. 234-264, doi: 10.1098/rstl.1767.0028.
  • On the Means of Discovering the Distance, Magnitude, & c. of the Fixed Stars, in Consequence of the Diminution of the Velocity of Their Light, in Case Such a Diminution Should be Found to Take Place in any of Them, and Such Other Data Should be Procured from Observations, as Would be Farther Necessary for That Purpose. In a Letter to Henry Cavendish, Esq. FRS and AS In: Philosophical Transactions of the Royal Society. Vol 74, 1784, pp. 35-57, doi: 10.1098/rstl.1784.0008.
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