viii CONTENTS 



PAGE 



Illusions of the Senses 149 



Taste and Smell ... 15 



Sense of Heat 15 



Sense of Hearing 15 



Sense of Touch One Thing Appearing as Two 151 



How Objects may be apparently Seen through a Hole in the 



Hand 156 



How to See (apparently) through a Solid Brick 158 



CURIOUS ARITHMETICAL PROBLEMS 



The Chess-board Problem l6 3 



The Nail Problem l6 4 



A Question of Population J ^5 



How to Become a Millionaire l66 



The Actual Cost and Present Value of the First Folio Shake- 

 speare l68 



Arithmetical Puzzles I 7 



Archimedes and His Fulcrum I7 1 



