LIST OF ILLUSTRATIONS. 



1. Eefraction of Parallel Rays by Plano-convex Lens, 



2. Ditto by Double-convex Lens, 



3. Refraction of Converging Rays, 



4. Refraction of Diverging Rays, 



5. Formation of Images by Convex Lenses. 



6. Spherical Aberration, 



7. Chromatic Aberration, . 



8. Section of the Achromatic Object-glass, 



9. Effect of Covering-glass, 



10. Action of Simple Microscope, 



11. Simplest form of Compound Microscope. 



12. Complete Compound Microscope, 



13. Huyghenian Eye-piece, . 



14. Ross's Simple Microscope, . 



15. Gairdner's Simple Microscope, . 



16. Field's Simple Microscope, . 



17. Quekett's Dissecting Microscope, 



18. Field's Compound Microscope, 



19. Highley's Hospital Microscope, 



20. Nachet's Compound Microscope, 



21. Smith and Beck's Student's Microscope, 



22. Ditto Dissecting Microscopi 



23. Waringtou's Universal Microscope, 



24. Ditto Ditto, . 



25. Ditto Ditto, 



26. Ditto Ditto, . 



27. Ross's Large Compound Microscope, 



28. Powell and Lealand's Ditto, . 



29. Smith and Beck's Ditto, 



30. Arrangement of Binocular Prisms, . 



31. Nachet's Binocular Microscope, . 



32. Draw-tube with Erector, 



33. Jackson's Eye-piece Micrometer, 



34. Microscope arranged for Drawing, . 



35. Ross's Achromatic Condenser, . 



36. Smith and Beck's Ditto, 



37. Powell and Lealand's Ditto, 



38. White-Cloud Illuminator, 



39. Amici's Prism, . 



40. Parabolic Illuminator, 



41. Fitting of Polarizing Prism, 



42. Fitting of Analyzing Prism, 



43. Selenite Object-Carrier, . 



44. BuU's-Bye Condenser, 



45. Ordinary Condensing Lens, 



46. Side Reflector, 



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