Page:Dictionary of National Biography, Second Supplement, volume 3.djvu/366

 university, and bequeathing to the latter ultimately his valuable collections and money to found a chair in geology. His health failed in the autumn of 1903, but he continued to write and work up his great stock of accumulated observations till within a few days of his death on 9 March 1908. He was unmarried.

Sorby's scientific work is distinguished by versatility and originality. His greatest advances were in geology, but ' scarcely any branch of knowledge or question of scientific interest escaped his attention : the use of the spectroscope in connection with the microscope ; the nature of the colouring matter in blood, hair, follage, flowers, birds' eggs, and minerals ; meteorological problems of all kinds ; improvements in blowpipe analysis and in the methods of detecting poisons.' Later, he collected marine plants and animals, preparing catalogues to show their distribution, devising methods for preserving them with their natural colours and exhibiting them as transparent objects, in which he was remarkably successful. But in addition to these he took up archaeological studies : the churches of East Anglia ; the evolution of mythical forms of animals in ancient ecclesiastical architecture ; Roman, Saxon, and Norman structures, and the characteristics of the materials employed in them ; while as amusements he collected ancient books and maps, and studied Egyptian hieroglyphics.

To geology has contributions were as valuable as they were varied. He discussed the origins of slaty cleavage, demonstrating by experiment that Daniel Sharpe [q. v.] was right in attributing it to pressure, of cone-in-cone structure, of impressed pebbles, of the magnesian limestone, and of the Cleveland ironstone. He also dealt with the nature of coccoliths in the chalk, questions of rock denudation and deposition, the formation of river terraces ; besides water supply, and the contamination of rivers by sewage. In working at the latter he spent about seven months in studying the lower Thames in connection with the royal commission on the drainage of London, and laid before that body a large amount of important evidence. But Sorby's most memorable work was in the field of petrology. William Crawford Williamson [q. v.] had already improved a process originated by William Nicol (the inventor of the Nicol polarising prism) of making thin slices of fossil wood for microscopic examination, and he applied it to some other organisms. Sorby visited Williamson in Manchester prior to 1849 and learnt the art. It occurred to him to try it on rocks, and in that year he made his first thin slice. The first result of this method of investigation was a paper, published by the Geological Society in 1851, on the 'Calcareous Grit of Scarborough.' It however excited little attention, and one on 'Slaty Cleavage' (1853) met with such a chilling reception that he published it elsewhere. Even his great paper 'On the Microscopic Structure of Crystals, &c.,' published in 1858, was ridiculed by many. In another decade he had gathered a small but enthusiastic band of disciples, both in England and on the Continent, and before he died was justly hailed as the father of microscopic petrology. He published several other important papers on the microscopic structure of rocks, notably his presidential addresses in 1879 and 1880 to the Geological Society on the structure of stratified rocks ; only three months before his death he communicated to that society a paper dealing with the quantitative study of rocks ; and last, but not least, he studied the microscopic structure of irons and steels, with results of great industrial value. This study was begun to illustrate meteorites, and it proved the latter to be a mixture when molten which became a compound on cooling. He had a Yorkshireman's shrewdness, but his willingness to help fellow workers and freedom from all self-seeking won him many friends. He was elected F.G.S. in 1850, received the Wollaston medal in 1869 and was president in 1878-80. He was president of the geological section of the British Association in 1880, and also filled that office in the Microscopical and the Mineralogical Societies. He was elected F.R.S. in 1857, and was awarded a royal medal in 1874. He was an honorary member of many foreign societies, receiving from Holland the Boerhaave medal. In 1879 the University of Cambridge made him an honorary LL.D. In 1898 his fellow- townsmen presented him with his portrait (now in Sheffield university, together with a marble bust), and the Geological Society at its centenary in 1907 sent an address to 'The Father of Microscopical Petrology.'