Sorby
Sorby, Henry Clifton
ACHIEVEMENTS:
Pioneer of microscopic techniques in geology
DATE AND PLACE OF BIRTH:
10 May 1826, Woodbourne, near Sheffield, Yorkshire, England
DATE AND PLACE OF DEATH AND AGE AT DEATH:
9 March 1908, Sheffield, Yorkshire, England. Aged 82
DISCIPLINE:
Geologist
FIELD:
Geology
LANGUAGE:
English
PARENTS:
Father: Henry Sorby
Mother: Amelia Lambert
SIBLINGS:
None
SPOUSE:
None
CHILDREN:
None
EDUCATION:
Local schools
Private tutor
MAJOR WORK:
"On the Microscopical Structure of Crystals" (1858)
LIFE AND TIMES:
When his father died in 1847 Sorby was twenty-one and had committed himself to a life of scientific research. A modest inheritance from his father enabled him to remain at home with his mother and conduct his investigations.
His most significant work was on the use of the microscope in geology and metallurgy. In the summer of 1849 Sorby began to study sedimentary rocks in the Malvern Hills. In the same year, he visited William Williamson who had developed the technique of preparing thin slices of fossil wood for microscopic examination.
George Sanderson*, a lapidary (stoneworker) in Edinburgh, had prepared sections of minerals in thin slices for examination in 1818, and the process was first publicized by Witham* in his "Obervations on Fossil Vegetables" in 1831. Sorby adapted this technique to rocks.
Unlike previous researchers such as the French paleontologist d'Orbigny*, Sorby did not examine rocks microscopically in order to find microscopical
organisms; he was concerned with the structure of the rocks themselves. He became involved in a debate on the causes of slaty cleavage and in 1853 he demonstrated that the cleavage was caused by the displacement of mica particles which occurred in pebbles of magnesian limestone and Cleveland ironstone under pressure.
In 1856 he was persuaded to attend a meeting of geologists and scientists in London where he discussed slaty cleavage with Babbage*. Sorby went on to investigate schists and metamorphic rocks, a study which resulted in his important paper on liquid inclusions in natural and artificial crystals (1858).
The chemist Davy* had earlier observed inclusions in large crystals but Sorby was the first to find inclusions in smaller crystals in many metamorphic rocks. The reason Sorby had discovered these inclusions was because he had conducted microscopic investigations of rock slices. His paper was illustrated with 120 drawings made under the microscope which he personally reproduced as lithographs.
Although his paper advocated the use of microscopic techniques in geological investigations, Sorby did not push the idea and many other geologists scoffed at the idea of applying a microscope to a mountain.
However, in 1861 Sorby visited the Rhine valley with his mother and met Zirkel*, a young German geology student. Zirkel was inspired by Sorby to use the microscope and five years later he published work which established the technique of petrography as a systematic science.
Sorby relied for his intellectual companionship on the local Literary and Philosophical Society which had fortnightly discussion meetings. In 1863 a discussion on ornamental etching and the manufacture of iron and steel appears to have been the stimulus for his investigations into metallurgy which he then undertook.
He analysed the composition of steel, and at a meeting of the British Association in Newcastle that year demonstrated that there were at least three separate crystalline compounds in steel. The following year he reproduced the structures of steel he had discovered as etchings. This was the first time that microstructures in iron had been recorded. The paper he read with his presentation mentions a large variety of iron and steel and can be said to be the origin of professional metallurgy. Again, Sorby left it at that, and no one else followed up his lead.
He now turned to spectrum analysis. His stimulus in this instance was the announcement in 1864 by Stokes* of the use of absorption spectra for studying organic substances. Sorby was delighted to find a new use for his microscope. In 1865 he developed a new type of spectrum miscroscope for examining the colouring matter in animal and plant tissues.
He discovered carotene and worked on chlorophyll, the colour of the sky and autumn leaves, human hair, algae and semi-precious stones. On a visit to London in 1867 he met the art critic and amateur geologist Ruskin* who was bowled over by the beauty of Sorby's records of the colours in leaves and flowers. He was also fascinated by what he called the "rainbow of blood". Sorby's investigations into minute blood stains involved him in a sensational murder trial in 1871.
Sorby's mother died in 1874 and after that he visited London more frequently. He was a member of the Royal Society and became president of the Royal Microscopical Society, the Mineralogical Society and the Geological Society.
In 1876 he published a paper entitled "On Unencumbered Research A Personal Experience" in which he advocated the joys of working as a self-directed researcher.
Sorby was able to pursue a career as a full-time independent research chemist, the joys of which were evident when he bought a yacht in 1878. For virtually the rest of his life he spent five months of each summer cruising off the east coast of Britain. He equipped the yacht with a laboratory and studied marine biology and geology, also becoming interested in architectural history based on the construction of historic buildings in East Anglia.
For the Royal Commission on the Thames he conducted investigations on silt and sewage flow in the Thames. He was still prominent locally in the north-east and in 1880 he was one of the founders of Firth College, the institution which later became part of Sheffield University.
He returned to his investigations of steel in 1882, identifying graphite and iron oxide in iron samples and describing the process of re-crystallization and transformation. He helped to clarify the structural origin of many kinds of iron and steel and after 1885 this work was taken up by other scientists.
Arising out of his work in marine biology, in 1889 he developed a technique for differentially staining biological tissues and for mounting soft-bodied organisms as permanent lantern slides for demonstration.
The last five years of Sorby's life were spent as an invalid, during which he wrote a major paper on sedimentary rock formation which was read at the Geological Society in London just before his death in 1908.
ASSESSMENT: Sorby is credited with being the founder of microscopic petrography.
EXTRA CONNECTIONS: None
ONELINER: HC Sorby, founder of microscopic petrography
BIBLIOGRAPHY:
Higham, Norman, A Very Scientific Gentleman, Pergamon Press, London, 1963
DSB