53. The Phantascope 185 54. Phantasmagoria (ROBERTSON) 194 55. Wizard Dance 198 56. Nostradamus and Marie de Médicis 201 57. The Arrangement of the Reversing Prism 203 58. The Goat Trick 205 59. How to see through a Brick 207 60. The Polemoscope 210 61. Protection against ill-natured People 213 62. 218 63. Anamorphosis 220 64. Effect of Cut Paper-work 225 65. Seditious Toys 229 66. Diorama 234 67. 237 68. Stereoscope 238 69. The Principle of the Refracting 239 Stereoscope 70. The Camera Obscura 243 71. Section of Camera Lucida 247 72. The Spectre—an Optical Illusion 269 73. How to produce Spectres 271 ------------------------------------------------------------------------ THE WONDERS OF OPTICS. -------------- PART I. THE PHENOMENA OF VISION. -------------- CHAPTER I. THE EYE. THE Eye is at once the most wonderful and the most useful of all our organs of sense. It is especially by means of the eye that we gain a knowledge of the exterior world. Our other senses are far more limited in their action: thus the sense of touch only extends to objects within our reach; the sense of taste is only a delicate and exquisite modification of the sense of touch; the sense of smell can only be exercised on substances that are close to us; and the use of our ears is limited by the distance at which the loudest sound ceases to impress them. But the eye has the privilege of extending its dominion, whether for mere enjoyment or for serious instruction, far beyond the limits of this little world. Not only is it the origin of all our ideas upon every object that comes within its ken; not only does it reveal to us our own position and that of our surroundings; but, thanks to the discoveries of modern science, it is able to admire, on the one hand, a world of infinite minuteness that remained unknown to us for centuries, and, on the other, the immeasurable immensity of the starry universe.