PREFACE TO THE SECOND 

 EDITION 



THIS second edition has been entirely revised. Although 

 this little book remains substantially the same, yet I 

 hope that the correction of some errors, the removal 

 of some obscurities, and the insertion of some additions, 

 will help to make it a more trustworthy and intelligible 

 introduction to the study of a vast subject of ever-increas- 

 ing interest. 



EDWIN S. GOODRICH. 



October 12, 1918. 



