LIST OF ILLUSTRATIONS. 



PAGE 



The Moon as seen by a Man who is " Fou " , . 223 



How to see a Hole through the Hand . . . 226 



Limitations of Sight : Mental Interpretations . ,234 



Liability of Interpretations to Error . . . .236 



Apparent Convergence of Cloud Lines . . .238 



A Law of Perspective . . . . -239 



Spherical Shape of the Sky Firmament . .241 



Variations in Apparent Steepness of Hills . ... . 244 



Discontinuity : Flower Petals and Scales of Moth's 



Wings . . . . . . ".".- . 247 



Experiment of Limitations of Hearing . . . 249 



The Nerves and Imperfect Sense of Temperature . 260 



A Handicap Race in the Pursuit of Science . . 267 



Space and Limits of Divisibility . . . . 273 



Discontinuity of Motion . . . . . 279 



The Valves in the Veins . . . . 290 



Mechanism of the Heart- valves . . . -295 



Correspondence between Human and Equine Limbs . 300 



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