Images Dated 22nd September 2007

Sir William Herschel, German-born British astronomer, (c1900)

Sir William Herschel, German-born British astronomer, (c1900). Portrait of Herschel and the Comet of 1831. Herschel (1738-1822) constructed his own telescope after taking up astronomy as a hobby. As well as discovering the planet Uranus in 1781 and two of its satellites, he performed a major study of Saturn. He discovered two satellites, the rotation of the planetary rings and the period of the planet's rotation. He also catalogued and investigated the motions of binary stars, the results of which are still in use. Trade card, one from a series on astronomers produced by Liebig extract of meat, (c1900)

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Elevation of Troughtons dividing engine, 18th century, (1886)

Elevation of Troughton's dividing engine, 18th century, (1886). Until the 1770s, scales on scientific instruments had been marked out by skilled craftsmen in a process called dividing, this was partly mechanized from the 1770s when dividing engines were introduced. Originally used on small instruments, by the 1850s they were used to graduate scales on large astronomical telescopes, making hand-dividing obsolete. This particular example was completed by John Troughton, and is similar to the first successful dividing engine which was completed in about 1775 by Jesse Ramsden. Illustration from Cyclopaedia of Useful Arts, Mechanical and Chemical, Manufactures, Mining, and Engineering, by Charles Tomlinson, Volume I, (Jamess Virtue, London, 1886)

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William Thomson, Lord Kelvin, Irish-Scottish mathematician, physicist and engineer, 1877

William Thomson, Lord Kelvin, Irish-Scottish mathematician, physicist and engineer, 1877. Kelvin (1824-1907) was a leader in the physical sciences of the 19th century. He did important work in the mathematical analysis of electricity and thermodynamics, and did much to unify the various theories of heat held by leading scientists of the time. Kelvin introduced the Kelvin or absolute scale of temperature, and discovered the Thomson effect in thermoelectricity. Also significant are his discoveries and improvements in the field of communication via submarine cables, and his invention of the reflecting galvanometer and the siphon recorder

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