114 PROCEEDINGS OF THE SOCIETY. 



Professor Cael Benedicks and Mr. Erik Walldow sent in a 

 paper entitled, " Some Points Concerning Sharpness in High Magnifica- 

 tion Micrographs." 



The investigations were started as a detailed and critical examination 

 of the new Reichert microscope, which is of the Le Chatelier type. It 

 was found to produce excellent results at the very highest magnifications. 



A note received from Professor F. Giolitti (Turin) suggested some 

 *' Alterations in the Design of the Le Chatelier Metallurgical Micro- 

 scope." 



The author considers this instrument preferable to other similar types 

 on the market, but two disadvantages should be removed ; one is the 

 sagging of the rack due to the weight of the stage, and the second 

 is the absence of an apparatus for easily and rapidly changing the 

 objective. An instrument is described which, while preserving the 

 principle of vertical observation, embodies these improvements. The 

 instrument can support on the stage several kilogrammes without causing 

 distortion. The fine focusing is effected by manipulating not the stage, 

 but the eyepiece tubes. 



Mr. Albert Sauveur (Harvard University) also sent in a note 

 suggesting " Improvements in Metallurgical Microscopes." 



The two types of microscopes used in the United States are described. 

 One of these is the horizontal-vertical type in which a vertical micro- 

 scope is used for visual and a connected horizontal camera for photo- 

 graphic work. The author's magnetic holder for iron and steel is largely 

 employed. 



Mr. Sauveur does not expect much from greatly increased magnifi- 

 t^ations of iron and steel. What is needed at the moment are better 

 methods for identifying constituents and impurities, and he briefly 

 indicates the gaps in our present knowledge. 



Mr. F, Ian C Rawlins, F.R.M.S., described how an Ordinary 

 Microscope can easily be Adapted for Metallographical Work. 



The adaptions suggested are a focusing substage fitting, a simple 

 'Carrier in which to mount the objective close to the reflector of the vertical 

 illuminator, and for illumination a type of half-watt lamp made in 

 Holland (used with a condenser of small aperture), in which the ring- 

 filament gives a very solid and concentrated source of light. 



Dr. W. H. Hatfield, in the course of the discussion, spoke of the 

 value of high-magnification photographs of iron and steel, but he 

 reminded the meeting that 1,000 diameters represented the limit of 

 adequate resolution — more than that only enlarged the picture. If 

 that resolution could be exceeded, he anticipated a considerable advance 

 in knowledge. Such problems as the cause of the influence of cold 

 work on metals still awaited solution. 



Professor H. M. Howe, in a communication to the meeting, also 

 indicated the value of aiming at higher magnifications. 



Mr. E. F. Law similarly alluded to the fine structure of modern 

 alloys, which could not be resolved with existing instruments. Similar 



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