METALLURGICAL MICROSCOPES AND THEIR DEVELOP- 

 MENT. 



By Leslie Aitchison, D. Met., B.Sc, A.I.C., and F. Atkinson. 



It is assumed that the primary function of this symposium is to 

 bring out the present position in regard to microscopes and also to 

 elicit those improvements which could well be introduced into micro- 

 scopes with a view to improving the instruments, making them more 

 convenient to employ, and also elaborating the uses to which they can 

 be put. The present notes are written from the point of view of the 

 metallurgist, and primarily from that of the working metallurgist, to 

 whom the microscope is of constant value and usefulness. No attempt 

 is made to discuss the questions from the optician's standpoint, but 

 rather to indicate the needs of the metallurgist in the hopes that the 

 optician and miscroscope manufacturer will be able to meet more and 

 more of these requirements. 



In. saying anything of modern microscopes it is difficult to avoid 

 constant reference to the products of the Continental makers, and to 

 make comparisons between their microscopes and those produced in 

 this country. This has reached the stage at which comparisons usually 

 take the form of stating how near the British article approaches to the 

 Continental. The position will not be really satisfactory until the 

 reverse of this position is the true one, i.e., until the British article is 

 compared with tlie Continental on the basis of the superiority of the 

 former and not upon its inferiority. 



Speaking as users of microscopes and microscopic outfits, one of 

 the first points that requires attention is the more prompt incorporation 

 in the instrument of those details and fittings which make the use 

 of a microscope less laborious. The Continental makers were always 

 ready to adopt and to incorporate these details, and it would be of 

 great assistance if the British manufacturers would do the same. 

 For instance, the Continental makers would supply a stage micrometer 

 in metal (a great improvement upon those made in glass), marked in 

 tenths and hundredths of a millimetre. The British manufacturer 

 has up to the present given us one marked only in tenths of a milli- 

 metre. 



A similar matter, and one that causes a good deal of trouble, is 

 the lack, upon photomicrographic outfits, of a really good, reliable 

 and workable fine focussing arrangement which can be operated from 

 the camera end. This objection applies to (ill microphotographic 

 outfits, British and Continental, as none of those made give real 

 satisfaction. For inetalhirgical work photomicrography is of great 

 importance, and if photographs are to be taken at high powers, 

 e.(f., up to 1,000 diameters, the focussing apparatus is of vital im- 

 portance. Those at present manufactured do not work really well, 

 and cause a great deal of irritation to the operator. 



152 



