ON THE STUDY OP ISOMORPHOUS DERIVATIVES OP BENZENE. 83 



containing halogens in the para-position have been similarly examined ; 

 also derivatives of the three isomeric benzenedisul phonic acids. 



In almost every case the crystal structure of these compounds can 

 be successfully interpreted in the light of the Barlow-Pope theory. 



A second memoir embracing the results of the investigation is now 

 in course of preparation. 



The Committee desire to express their thanks especially to Messrs. 

 Colgate and Eodd and also to Mr. Mummery for the assistance they 

 have rendered in the inquiry during the year. 



The Influence of Carbon and other Elements on the Corrosion of Steel. — 

 Report of the Committee, consisting of Professor J. 0. Arnold 

 {Chairman), Dr. W. E. S. Turner {Secretary), Professor W. P. 

 Wynne, Professor A. McWilliam, Mr. C. Chappell, and Mr. F. 

 Hodson. 



The subject of the corrosion of iron and steel is one that is rapidly 

 engaging considerable attention in the metallurgical world, the 

 researches of Friend, Cushman, Walker, Longmuir, and others having 

 brought it deservedly into considerable prominence. Despite the fact, 

 however, that the modern metallurgy of iron and steel largely centres 

 about the influence of various alloying elements upon its physical and 

 mechanical properties, no reliable data are available as to the influence 

 exerted by them upon its corrodibility. In view of the absence of such 

 data regarding the influence of carbon, in gradually ascending per- 

 centages, upon the corrodibility of iron, and especially in view of the 

 fundamental importance of carbon as an iron-alloying element, the 

 Committee have confined their attention solely, during the past year, 

 to the investigation of the influence exerted by this element upon the 

 corrodibility of iron. 



An attempt was made by Andrews * to obtain some data regarding 

 this question, and his results were published in 1885 in a paper on 

 ' The Corrosion of Metals during Long Exposure in Sea-water ' — one of 

 a series of brilliant and systematic researches on corrosion which are 

 unfortunately not so well known as they deserve to be. His ascending 

 carbon series, however, included such widely diverse materials as 

 Wrought Iron, Siemens and Bessemer Steels, and also Crucible Cast 

 Steels, in which the percentages of Si and Mn vary considerably, rising 

 as high as 0'4 per cent, and 1"3 per cent, respectively, whilst the S and 

 P in some cases respectively reach such abnormal figures as 012 per 

 cent, and 0'27 per cent. each. The values given by such a series can 

 hardly be relied upon as being indicative of the influence of carbon 

 alone upon the corrodibility of iron. 



A series of pure iron -carbon alloys have, therefore, been obtained 

 by the Committee in order not only to indicate the influence of carbon 

 upon the corrodibility and other properties of iron but to serve also 



1 Proc. Inst. Civil Eng., vol. 82, p. 281. 



Q 2 



