September 27, 1906J 



NA TURE 



543 



announced, and the quanlilative composition of 

 Sorby's pearly constituent determined. This paper 

 is admitted on all sides to be a classic. 



In 1896, in " The Influence of Impurities on Gold 

 and Copper " (Arnold and Jefferson), the first micro- 

 ijraphic investigation of gold alloys was described, and 

 Ihe discovery of brittle intercrystalline cements ren- 

 dered void atomic volumes as an explanation of the 

 results. 1897 produced " The Influence of Sudden 

 Cooling- on Nearly Pure Iron " (Arnold), and " TTie 

 Permeability of Steel-melting Crucibles " (Arnold and 

 Knovvles), which showed a method for quantitatively 

 measuring the volume of gas permeating the walls of 

 crucibles 4'-inch thick during metallurgical operations. 

 " The Micro-chemistry of Cementation " was read in 

 1898, and the discovery of the cause of the decay of 

 certain metals used in marine construction in con- 

 nection with the disastrous explosion on the S.S. fro- 

 dano was given in a report to Lloyd's. " The 

 Diffusion of Elements in Iron " (Arnold and 

 McWilliam, iSqq) divided the elements of steel into 

 fixed and migratory groups and confirmed Prof. Camp- 

 bell's diffusion of sulphide phenomena. During this 

 research two very important phases of carbide inter- 

 penetration at different temperatures were discovered, 

 and also a hitherto unsuspected segregation point 

 which has cleared up some of the occasional mysterious 

 failures of the highest grade cutting edge steel. 



" The Properties of Steel Castings, Part i." (.Arnold, 



1901) dealt with pure iron and carbon castings, and 

 showed their unsuitability for general commercial 

 work. " The Micro-structure of Hardened Steel " 

 (.Arnold and Mc\\'illiam, 1902), amongst other things, 

 first showed the cementite in the so-called austenite 

 martensite structure. " The Elimination of Silicon in 

 the Acid Open Hearth " (McWilliam and Hatfield, 



1902) is an interesting study, under works conditions, 

 of chemistry at high temperatures in the reaction 

 of metal and slag on each other, in which a balance 

 point in the composition of the slag was discovered, 

 such that with more base C, Si, and Mn were elimin- 

 ated from the metal, whilst with more acid C could 

 still be eliminated, but Si and Mn were reduced and 

 returned to the bath. " Tlie Influence of Sulphur and 

 Manganese on Steel " (.'Xrnold and Waterhouse) and 

 " On the Dangerous Crystallisation of Steel " (.Arnold) 

 were produced in 1903, and in the latter the author 

 announced his now well-known method for recording 

 results of steel under alternating stress, the stress 

 being greater than the elastic limit instead of less, 

 as is the case in other methods. " Acid Open Hearth 

 Manipulation " (McWilliam and Hatfield, 1904) is 

 another high temperature chemistry study on a 

 25-ton furnace, with unusual bases, in which also it 

 was shown that the nature of the ingot is not merely 

 a function of its composition as ordinarily determined, 

 but varies with the history of the charge in a special 

 manner shown. " The Thermal Transformations of 

 Carbon Steels " (.Arnold and McWilliam, 1904), too 

 complex to describe in a sentence, shows the nature 

 of the transition forms of the constituents of steels 

 by quenching so as to trap several forms in one 

 small section, where they can be studied somewhat 

 after the manner of examining rock changes over a 

 tract of country. Winder and Brunton did early work 

 on open hearth chrome steel castings; Longmuir here 

 worked out what had been borne in upon him by his 

 works experience, resulting in his two researches on 

 " The Influence of Casting Temperature on the 

 Properties of Metals and Alloys "; Baker did his work 

 on "The Influence of Silicon on Iron," and half the 

 work resulting in Ibbotson and Brearlev's well-known 

 book on " The Analysis of Steel Works Materials " 

 is of this laboratory. The above i'; not bv any means 



NO. 1926, VOL. 74] 



a complete list, but is intended to indicate the prin- 

 cipal and to give a good idea of the original work 

 done, which has been acknowledged by practical as 

 well as by professional men to have had great and 

 important influence. 



With regard to the students trained, every works of 

 any importance in the district has its quota of them, 

 and many are reflecting great credit on their school 

 by the success with which they are holding responsible 

 positions. There is no doubt that all firms of import- 

 ance, having ready at hand well-trained men, formed a 

 potent factor in the signal success with which Sheflield 

 not onlv repelled the .American invasion of high speed 

 steel, but was able promptly and successfully to carry 

 the war into the enemy's territory. The associateship 

 in metallurgy has always been kept up to about the 

 standard of an honour examination, no second classes 

 being allowed, and the fight for the Mappin medal 

 and 15!. premium given to the head associate of the 

 year is long and severe. This medal and premium was 

 founded by Sir Frederick Mappin, Bart., who has con- 

 sistently for more than twenty years used not only his 

 wealth, but his great influence with others, and his 

 foresight and dogged perseverance, in furthering the 

 cause of this technical department. His recent pur- 

 chase and practical presentation of the adjacent 

 Caledonian Works has enabled the authorities to apply 

 their fifteen years' experience during the erection of a 

 new and magnificent teaching plant, which has been 

 so recently described that it need not have further 

 mention here. Finally, as to the attitude of manu- 

 facturers, few who followed with interest the doings 

 of fifteen years ago would have prophesied that steel 

 makers would send for associates at the end of each 

 session, or that some even would ask for " your 

 medallist of the year if possible," but such is the fact 

 to-day. 



All Sheffielders asked feel certain that but for the 

 continued success of this and the technical depart- 

 ment as a whole, Sheffield would never have success- 

 fully demanded a university, and that, indeed, the 

 university inaugurated by the King on July 12, 1905, 

 may be taken as a monument to one of the influences 

 of the technical department. Twice in its history has 

 this progressive department had to sever its connec- 

 tion with constituted authority, and many are looking, 

 somewhat anxiously it must be confessed, to its pro- 

 gress under the cumbrous machinery of university 

 government, with its several forms of outside inter- 

 ference. Change and progress are not now decided 

 upon by those immediately interested, for at least a 

 majority of a governing body, composed of professors 

 of all and sundry, must sanction all decisions, and in 

 its elTect on this hitherto uniformly progressive and 

 successful department university government is un- 

 doubtedly on its trial, so far as its influence on the 

 application of science to industry is concerned. 



EARTH-EATERS IN INDIA. 



UNDER the name of geophagy or earth-eating 

 are comprehended a number of customs of very 

 different origin and meaning. In practically every 

 part of the world is found the habit of eating finely 

 divided mineral substances in bulk, and not merely in 

 small quantities as condiments; but the purpose differs 

 no less widely than the condition of the eaters as re- 

 gards age, sex, or health before and after acquiring" 

 the habit. We learn from Pliny that the Romans 

 mixed corn with chalk from near Puteoli ; Lemnian 

 and Armenian earths, on the other hand, were famous 

 for medicinal purposes — the use of the former has been 

 continued to our own day; in South America clay sup- 

 plies the place of food during floods; in Borneo and 



