QUESTIONS 



1. Why is it worth while to attend to points which make only a small 

 improvement in the microscopical image? 



2. Name 20 chief points which should be attended to, in order to 

 get the optimum image in the microscope. 



3. Why should the microscopist use a low-power Greenough binocu- 

 lar in his early studies, as much as possible? 



4. Name nine procedures which would have to be leariied in (jrder 

 to obtain nearly perfect microscopical images. 



5. Contrast the results of disregarding and of attending to the main 

 rules of scientific microscopy. 



6. How is a binocular magnifier superior to a single-lens achromatic 

 magnifier of equal correction? 



7. What superiority has the low-power Greenough binocular over 

 the low-power objectives on the monocular microscope? 



8. What are the advantages of shielding the unoccupied eye by 

 ground glass when using a single magnifying lens? 



9. What advantages has a corrected hand lens over an uncijrrected 

 one? 



10. What are the peculiar advantages of using a Steinheil triplet as a 

 hand lens? 



11. What low-power magnifier may be found most suitable for dissec- 

 tion and drawing? 



12. What kind of lens is useful for magnifications of 3 or 4 times? 



13. Why should a hand lens be held as near the eye as possible? 



14. What is the aperture of a hand lens? 



15. Contrast the use of a hand lens when the optical rules are disre- 

 garded, and when they are attended to. 



16. What is working aperture? 



17. What is maximum useful magnification? 



18. Why should the source of light be equal to the source-field? 



19. What is the condenser light circle? 



20. What is the objective (aperture) circle? 



21. What are the eyepiece circles, and how can they be readily 

 observed? 



22. Where is the eyepoint? 



23. What is the permissible maximum size of the eyepiece circles? 



24. When can an achromatic drij condenser be advantageously 

 emjiloyed? 



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