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Sorby, Henry Clifton

metallography studying steel iron

(1826–1908) British geologist and metallurgist: created petrological microscopy and metallography.

Sorby was born and lived in Sheffield, Yorkshire, then a town and dominated by steel-, tool- and cutlery-making. His family had been cutlers since the 16th-c, but the business was sold in 1844; as a result, Sorby was wealthy, allowing him to become an archetypal Victorian gentleman-amateur scientist, with wide-ranging interests largely in geology but including forensic work, archaeology, optics and marine biology. Most notably, he fathered metallography, sedimentology and microscopical petrography. His first published research, done in his early 20s, was on the deposition of water-borne sediments, which form sedimentary rocks, on which he experimented, in part using the River Rother on his estate. At this time he also studied limestones (notably present in his home area) by microscopy, concluding that they are formed from minute organisms (mainly coccoliths). Like his other geological ideas, these are now fully accepted; then they were controversial.

However, it is his work in making and studying thin rock sections and polished metal surfaces that is best known and that created petrography and metallography respectively. By the 1850s he had developed cutting methods used for fossil woods and gemstones to make for himself rock sections down to one-1000th of an inch thick. Examined by transmission microscopy (especially using a microscope fitted with the new polarizing prisms, which he had by 1861), minerals gave Sorby much new information, especially on the origin of slates and granites. Petrologists have used his methods ever since, despite a slow early acceptance of them.

In the 1860s he became interested in meteorites, as igneous rocks from outside the Earth. Many contain an iron–nickel alloy, and at about the same time Sorby was examining locally made iron and steel samples, whose polished or acid etched surfaces revealed their structure. He was later the first to show, in the 1880s, that carbon steel is a two-phase alloy, with its phases identified by him as iron and iron carbide: metallography had really begun.

In the 1860s he devised spectroscopic methods for detecting traces of blood. However, spectroscopy also led him into error. Studying zircons, and especially jargons from Ceylon, he found absorption lines, which he at first thought arose from a new element, jargonium. Strongly pressed by to publish this idea, he did so in 1869. Within the year, he realized that ‘jargonium’ was in fact uranium. The ‘jargonium fallacy’ was his only major error in research, and it injured the credibility of his blood tests for forensic use.

Sorby bought a yacht in 1878 and afterwards spent 6 months each year sailing, with marine zoology and work on tidal flow and estuary sedimentation included. On shore, he was the central figure in creating Firth College, which became Sheffield University.

When he died he had published over 150 papers on a great range of topics, over 62 years: and ridicule was no longer directed to ‘the strange idea of studying mountains and railway lines with a microscope’.

Sorrell, Maurice(c. 1914–1998) - Photographer, Chronology, Captures the Civil Rights Movement through the Lens [next] [back] Sooner or Later

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