202 Henry Clifton Sorhy, LL.B., F.R.S., F.G.8., etc., 



" To THE Father of Microscopical Petrography. 



"We the undersigned, assembled to celebrate the Centenary of the Geological 

 Society of London, desire to unite in expressing our profound conviction of the 

 important service rendered to the branch of science Avhieh they cultivate by 

 Dr. Henry Clifton Sorby. They deplore the circumstances which prevent him from 

 joining them on this occasion, but beg to be allowed to assure him of their great 

 admiration of his life's work, of their filial I'egard, and deep affection. They rejoice 

 to know that he still finds consolation and happiness iu his labours of love in 

 connection with the promotion of scientific research and education. 



"Arch. Geikie, P.G.S. 



F. Zirkel, Leipzic. J. W. Judd, Kew. 



W. J. Sollas, Oxford. J. P. Iddings, Chicago. 



W. L. Brogger, Kristiania. T. G. Bonney, Cambridge. 



Whitman Cross, Washington, D.C. F. Loewinsou-Lessing, St. Petersburg, 



Frank D. Adams, Montreal. A. Harker, Cambridge. 



F. W. Eudler, London. T. McK. Hughes, Cambridge. 



H. Arnold Bemrose, Derby. J. W. Evans, London and Bolivia. 



A. Wichmann, Utrecht. Grenville A. J. Cole, Dublin. 



A. Lacroix, Paris. F. H. Hiitch, Johannesburg. 



H. A. Miers, Oxford. J. W. Gregory, Glasgow. 



J. S. Flett, London. G. T. Prior, London. 



J. J. H. Teall, London. Hans Reusch, Kristiania. 



C. Barrois, Lille. C. Velain, Paris. 



G. F. Becker, Washington, D.C. W. W. Watts, London." 



From the dinner given to the assembled geologists by the Geological 

 Society Club at its Centenary Meeting a telegram of recognition and 

 condolence was also sent to their veteran associate, confined to a sick- 

 room, and these marks of esteem and affection afforded him intense 

 pleasure. 



Many other problems of geological science were attacked by Sorby, 

 during his long and busy life, with more or less success. Among these 

 we maj' notice the pseudomorphous origin of the Magnesian Limestone 

 and Cleveland Ironstone, the nature of the Coccoliths in the Chalk, 

 the origin of Cone-in -cone structure, the mode of formation of impressed 

 pebbles, many questions connected with denudation and the deposition 

 of rocks, the formation of river terraces, and practical enquiries with, 

 respect to water supply and the contamination of rivers by sewage. 

 Even in those cases where his solution of difficulties may not produce 

 conviction in the minds of the readers of his papers, they cannot but 

 be impressed by the ingenuity of the methods of inquiry which he 

 devised. 



But Sorby's work was by no means confined to geology. 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 matters in blood, hair, foliage, 

 flowers, bird's eggs, and minerals ; meteorological problems of all 

 kinds ; improvements in blowpipe analysis and in tlie methods of 

 detecting poisons, were among the subjects treated of in papers 

 written by him between 1860 and 1879. In this latter year, after 

 the death of his mother, Sorby, who had removed from Woodbourue 

 to Broomfield in Sheffield in 1853, bought a yacht, and from that time 

 forward spent nearlj^ half the year on the water. His ^^acht, the 

 " Glimpse," was, however, nothing but a floating study and laboratoiy, 

 which enabled him to widen the sphere of his researches and find new 



