Improved Metallurgical Microscope. By Walter Bosenhain. 155 



system. Upon the stage itself, and therefore partaking of its 

 mechanical movements, is fixed a second or raised stage with 

 apertures to fit over the condenser just described. With this 

 attachment the only disadvantage is that the range of separation 

 between tube and stage is diminished by about 50 mm. (2 inches), 

 but since the maximum separation is still 70 mm. (2f inches) this 

 diminution will hardly be felt for work with transmitted light. 

 All the advantages of extreme rigidity and concentric fine-adjust- 

 ment are of course retained when the instrument is used for trans- 

 parent objects, so that where one instrument is to be used for both 

 classes of work, the considerable gain for the study of opaque 

 objects which this Microscope is believed to afford, would more 

 than outweigh the slight disadvantages, if any, which will be 

 found in using it for transparent objects. 



In conclusion, the author would express his indebtedness to 

 Messrs. E. and J. Beck, Ltd., for the skilful manner in which they 

 have worked out all the details of the instrument from the 

 sketches and specification supplied to them. 



