SIR ROBERT HADFIELD, BART. 117 



Barrett and Tchernoff on the intimate relationship existing between 

 recalescence and the hardening of steel, and also the work of Guthrie 

 oneutectics led to the idea that both igneous rocks and alloyed metal 

 are the products of the crystallisation of mixed solutions. Bunsen, 

 and subsequently Vogt of Christiania, called attention to the laws 

 which control the crystallisation of minerals in slag, and when Teall 

 in 1888 pointed out the similarities of structure between graphic 

 intergrowths and Guthrie's eutexia of Metals, the application of the 

 solution hypothesis to rocks became apparent. In the domain of 

 Metallurgy, the introduction of the Thermocouple by Professor 

 le Chatelier led to the study of the Thermal Changes which accompany 

 physical or chemical variations of constitution within the metal. 



Sorby, in his Paper contributed to the Iron and Steel Institute 

 in 1887 and published in Vol. I of the Journal for that year, stated : 



''It is now twTuty years since I commenced to carefully study 

 the microscopic structure of Iron and Steel. The first object was 

 the study of meteoric iron, but I soon found that the results were of 

 even more value in connection with practical metallurgy." 



Again, on page 276 of the same volume, he says : 



" I regard that even a power of 400 linear fails to show whether 

 the pearly constituent remains unaltered or broke up into verv fine 

 laminae when very suddenly cooled. It either does not or the laminae 

 are too thin to be recognised. The changes in structure produced by 

 hardening deserve far more study, but will I fear tax to the utmost 

 the capabilities of the Microscope since the constituent grains of 

 hardened steel are so extremely minute." 



At this stage Sorby's work on Metals received recognition and 

 exerted a powerful influence. It became evident that the mechani- 

 cal properties of Iron and Steel depend upon the properties of their 

 crystalline constituents, and at this period the nomenclature of metal- 

 lography was developed. The subsequent work of Raoult, Van't 

 Hoff, Gibbs, etc., led to a tendency to decry the nomenclature as 

 unscientific. Nevertheless, it is still used and serves well for the ready 

 specification of different qualities of steel. 



Professor Judd, who was a friend of Sorby, has given some inter- 

 esting reminiscences of the conditions under which Sorby worked. 

 Apropos of Sorby's Laboratory, he remarked : " You speak of Sorby's 

 laboratory. All his work, when I knew him, was done in a private 

 room in his house ; there everything was as simple as WoUaston's 

 — a table with his Microscope, and a few bits of apparatus lying 

 about." 



In the same connection, Judd also remarked : " I went to Sheffield, 

 as a Chemist to the Cyclops Works, straight from the Jermyn Street 

 School of Mines in the Summer of 1864, and at once met Sorby. He 

 not only taught me to make rock-sections, but showed me what he was 

 doing with artificial irons— led to it by his studies of iron-meteorites. 

 Mr. George Wilson, then manager of Cammells, a very enlightened 

 man, gave me permission to supply Sorby with any irons that I 

 analysed, for his work, so that I saw the beginning of his Metallurgical 

 work — a very pleasant reminiscence. Down to the time that Ward 



