SECTIONAL TRANSACTIONS. 



SECTION A. 

 MATHEMATICAL AND PHYSICAL SCIENCES. 



Thursday, September 2. 



Symposium on X-ray methods and industry (lo.o). 



Sir William Bragg, O.M., K.B.E., Pres.R.S.— T/je application of 

 X-ray methods to industry. 



The X-rays supply new methods of examining the structure of a solid 

 material. As a result we obtain details of the mutual arrangements of the 

 atoms and molecules forming the design, and, in particular, we' prove the 

 existence of any of the regularity of arrangement which constitutes crystal- 

 linity. These matters are of importance to industry, since the properties 

 of all materials depend ultimately on molecular arrangement. The X-ray 

 methods have a number of useful features. They do not, for example, 

 disrupt the specimen ; they are content with minute amounts of material ; 

 they analyse in terms of molecules as well as of atoms and so on. On the 

 other hand, the minute dimensions of themselves and of the details which 

 they reveal are so widely separated from the dimensions of ordinary practice 

 that it takes time to make connection between them, and as a consequence 

 of their fundamental nature their application to industry is rather by way 

 of their effect on industrial science than, at present, on workshop practice. 

 The latter use is however considerable and the former is very great. 



Dr. G. Shearer. — X-rays and the metal industry (10.20). 



The use of X-ray diffraction methods in the study of metals provides 

 a variety of information much of which cannot readily be obtained by other 

 methods. Such studies give directly the arrangement of the atoms in the 

 metal and show how this arrangement alters when, for example, other 

 constituents are added to a pure metal to form an alloy. Less fundamental 

 in nature but, at times, of more immediate appHcation to industrial purposes, 

 is the further information which such examinations yield. By means of 

 X-rays it is possible to trace the effects on the structure of such processes 

 as heat treatment, cold working, hardening and the like. The size, the 

 state of perfection and the distribution in direction of its crystallites all have 

 an important bearing on the properties of a metal, and by giving information 

 on these aspects. X-rays extend the knowledge derived from studies with 

 the microscope and help towards an understanding of the magnetic, electrical 

 and tensile properties of the metal. 



