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PREFACE. 



rpHIS book contains descriptions of various problems of the kind 

 -■- usually termed Mathematical Recreations, and a few Essays 

 on some analogous questions. I have excluded all matter which 

 involves advanced mathematics. I hasten to add that the con- 

 clusions are of no nrantical nsp. anr[ that most of the results are 

 .^ roceeds further he is at least 



link I may say that many of 

 ;ing, not a few are associated 

 ithematicians, while hitherto 

 i not been easily accessible to 

 r matter has been added since 

 t insertions made since 1911, 

 ave had to be placed where 

 room ior raem coma DesTi oe iouna. 



In the first nine editions the book was divided into two parts, 

 most of the second being devoted to questions of a historical 

 character. There is ample precedent for including such matter 

 in books of mathematical recreations, but I have long felt that 

 much of the interesting and out-of-the-way information there 

 brought together would find a better place elsewhere. Accord- 

 ingly in this edition I have given up the division into two parts, 

 and have struck out most of the chapters in the second part such 

 as those on calculating machines, parallels, hyperspace, atoms and 

 ether, time and time measurers, etc. : earlier editions are acces- 

 sible for the matter now omitted. 



As now presented, the book contains only sixteen chapters, of 

 which the subjects are shown in the Table of Contents. Several 



