MICROSCOPE FOR MEASURING BRINELL IMPRESSIONS. 



(Constructed by the Societe d'Optique et de Mecanique 

 de Haute Precision, Paris.) 



The apparatus consists of two principal parts : the microscope 

 properly speaking, and the limb or support. 



The microscope itself comprises a mount D, carrying below an 

 objective 0, and above a micrometer P and an eye-piece Q. The 

 objective is aplanatic and achromatic, and yields a linear magnifica- 

 tion of 2.5. The micrometer has a length of 20 mm., which is divided 



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into 160 equal parts; numbers from to 8 are marked every 20th 

 division, so that a diameter of 8 mm. maximum can be measured 

 within 1/20 mm. The positive eye-piece imparts to the whole system 

 a total magnification of 21. The eye-piece rests in a small mounting 

 M, which can glide in the tube D for adjusting the eye-piece with 

 respect to the micrometer. 



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