CONTENTS. 



the object revolve. 39. Object to 

 be successively viewed by increasing 

 powers. 40. Slides to be cleaned. 

 41. Compressor. 42. Apparatus 

 for applying voltaic current. THE 



ILLUMINATION OF OBJECTS : 43. 



Curious effects of light on objects. 

 44. Illumination by transmission 

 and reflection. 45. Microscopic ob- 

 jects generally translucent, or may 

 be made so. 46. Effects of varying 

 thickness. 47. Varying effects of 

 light and shade. 48. Uses of the 

 Lieberkuhn. 49. Effects of diffrac- 

 tion and interference. 50. Use of 

 daylight. 5 1 . Artificial light. 

 52. Protection of the eye. 53. 

 Pritchard's analysis of the effects of 

 illumination. 



CHAP. IV. Pritchard's analysis of the 

 effects of illumination (continued). 

 MEASUREMENT OF OBJECTS : 54. 

 Measurement distinct from magni- 

 fying power. 55 ., Measurement by 

 comparison with a known object. 

 56. Micrometric scales. 57. Thin 

 glass plates. 5 8 . Micrometers . 

 59. Le Baillifs micrometer. 60. 

 Jackson's micrometer. 61. Mea- 

 surement by the camera lucida. 

 62. Goniometers. MAGNIFYING 

 POWER : 63. This term much mis- 

 understood. 64. Its exact meaning. 

 65. Least distance of distinct 

 vision. 66. Visual estimate of 

 angular magnitude. 67. Method of 



determining magnifying power by 

 the camera lucida. 68. Dimen- 

 sions of the least object which a 

 given power can render visible. 

 CHAP. V. MICRO POLARISCOPE : 69. 

 Polarisation. 70. Condition of a 

 polarised ray. 71. Polarisation by 

 double refracting crystals. 72. 

 Their effect upon rays of light. 73. 

 The micropolariscope. THE MOUNT- 

 ING OF MICROSCOPES i 74. Conditions 

 of efficient mounting. 75. Frauen- 

 hoffer's mounting. 76. Methods of 

 varying the direction of the body. 

 CHEVALIER'S UNIVERSAL MICROSCOPE: 



77. Mounting of this instrument. 



78. Method of rendering it vertical. 

 79. Method of adapting it to the 

 view of chemical phenomena. 80. 

 Method of condensing the light upon 

 the object. Ross's IMPROVED MI- 

 CROSCOPE : 81. Useful labours of 

 Mr. Ross. 82. Details of his im- 

 proved microscope. 



CHAP. VI. 83. His object-glasses. 

 MESSRS. SMITH AND BECK'S MICRO- 

 SCOPE : 84. Their largest and most 

 efficient instrument. 85. Their 

 smaller microscope. 86. Their ob- 

 ject-glasses. 87. Varley's micro- 

 scope. M. NACHET'S MICROSCOPE : 

 88. Their adaptation to medical and 

 chemical purposes. 89. Multiple 

 microscopes. 90. Double micro- 

 scope. 91. Binocular microscope. 

 92. Triple and quadruple microscopes. 



MICROSCOPIC OBJECTS. 



1. Microscopic objects. 2. The dragon- 

 fly and its larvse. 3. The satyr. 



4. The linceus sphericus. 5. The 

 lurco, or glutton. 6. The water-fly. 



SOLAR MICROSCOPE. 



. Its utility. 2. The principle of its 

 performance. 3. Why the magic 

 lantern does not serve the same pur- 

 poses. 4. The illuminating appa- 

 ratus. 5. How to protect the 

 object from heat. 6. The ampli- 

 fying apparatus. 7. The adjust- 



ments. 8. The screen. 9. The 

 reflector. 10. Method of mounting 

 the instrument. 1 1 . Arrangements 

 for the room of exhibition. 12. 

 Preliminary adjustments. 13. The 

 oxy-hydrogen and electric micro- 

 scopes. 



