PREFACE. 



IT is scarcely necessary for me to explain the plan of the 

 present work, because I have already in introducing my 

 ' Light Science for Leisure Hours/ my ' Science Byways,' and 

 my * Pleasant Ways in Science ' described the method on 

 which, as I think, such treatises as the present should be 

 written. This work deals with similar subjects in a similar 

 way ; but I think the experience I have acquired in writing 

 other works on the same plan has enabled me to avoid some 

 defects in the present work which I have recognised in the 

 others. 



The list of subjects indicates sufficiently the range over 

 which the present volume extends. Some of them might 

 be judged by their names to be in no way connected with 

 science, but it will be found that none have been treated 

 except in their scientific significance, though in familiar 

 and untechnical terms. 



RICHARD A. PROCTOR. 



S.S. 'ARIZONA,' IRISH SEA 

 October 18, 1879. 



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