i\r CONTENTS. 



MICROSCOPIC DRAWING AND ENGRAVING. 



PAGE 



CHAP. I. 1. Beautiful precision of the minute structure of natural 

 objects. 2. Cornea of a fly's eye. 3. Number of eyes of diffe- 

 rent insects. 4. Astonishing precision of artificial objects. 5. 

 Demand for such objects by Microscopists. 6. Classes of suck 

 artificial objects. 7. Microscopic scales. 8. Method of engraving 

 them. 9. Measurement of microscopic objects with them. 10. 

 Their minuteness. 11. Scales of Mr. Froment. 12. Rectangular 

 scales. 13. Micrometric threads. 14. Necessity for microscopic 

 tests. 15. Test-objects. 16. Telescopic tests ; double stars. 

 17. Nebulae and stellar-clusters. 18. Effects of different tele- 

 scopes upon them : telescopes of Herschel and Lord Rosse. 19. 

 Remarkable nebulae described by Herschel. 20. Differently seen 

 by Lord Rosse. 21. Microscopic tests. 22. Improved powers 

 of microscope. 23. The Lepisma-Saccharina. 24. ThePodura, 

 or Spring-tail 49 



CHAP. II. 25. Natural tests not invariable. 26. Natural tests 

 imperfect standards. 27. Nobert's test-plates. 28. The degree 

 of closeness of their lines. 29. Their use. 30. Apparent error 

 respecting them. 31. Froment's microscopic engraving. 32. 

 Method of executing it. 33. Various methods of microscopic 

 drawing. 34. Drawings by squares. 35. Dr. Goring's drawings. 

 36. Structure and metamorphosis of insects. 37. The day-fly. 

 38, The larva of this insect. 39. Its organs of respiration. 

 40. Its general structure. 41. Its mobility. 42. State of chry- 

 salis. 43. The perfect insect. 44. The production and deposi- 

 tion of its eggs, and its death. 45. Death may be delayed by 

 postponing the laying of the eggs. 46. They take no food. 47. 

 Their countless numbers ; their bodies used as manure . . 65 



CHAP. III. 48. The beetle. 49. Its larva. 50. Drawing of it in 

 its natural size. 51. Dr. Goring's magnified drawing. 52. 

 Production of the beetle from the egg. 53. The young larva. 

 54. Its voracity and manner of seizing its prey. 55. De- 

 scription of its organs. 56. Its chrysalis. 57. Water-beetle. 

 58. Gnat. 59. Dr. Goring's method of drawing. 60. Draw- 

 ing by the camera-lucida. 61. Section of the human skin ; 

 sweating-gland and duct. 62. The itch insect. 63. Method of 

 obtaining it . . . . . . . . . -81 



CHAP. IV. 64. Structure of the itch insect. 65. Its habits. 

 66. The mange insect. 67. Its form and structure. 68. Defects 

 incidental to drawing with the camera. 69. Microscopic photo- 

 graphs. 70. Microscopic daguerreotypes by Messrs. Donne and 

 Foucault. 71. Description of the blood. 72. Red and white 

 corpuscles. 73. Daguerreotype of a drop of blood magnified. 

 74. Magnitude of the corpuscles. 75. Cause of the redness of 



