Preface vii 



The work as now presented was practically completed in 

 June, 1914, and in that month a sealed copy was deposited in 

 the vaults of one of the learned societies, where it now remains. 

 But some statistics and results bearing on plant and animal 

 distribution, as well as some questions dealt with in Chapter 

 X, had to be supplied later. These were added to and de- 

 posited w4th the above in July, 1916. Since that time only a 

 few footnotes have been appended in small type and while the 

 work was passing through the press. So the conclusions pre- 

 sented in Chapters XXI to XXX have been in no way de- 

 termined by the iniqtiitous international struggle of the past 

 three years. The writer cannot but hope, however, that some 

 of his views may find the more ready acceptance, in virtue of 

 the melancholy spectacle presented by the nations in this 

 Twentieth Century of Christ's Era. 



The writer would now make hearty and grateful acknowledg- 

 ment of the kind help and encouragement extended by his 

 friends Dr. Henry W. Cattell and Mr. Roberts Le Boutillier, 

 for without their sympathetic aid this volume could not now 

 have seen the light. He also expresses sincerest thanks to his 

 friend Dr. Joseph Hepburn, who willingly volunteered to re- 

 vise proofs, and by his expert chemical knowledge has furnished 

 not a few valuable corrections and suggestions from the chem- 

 ical standpoint. 



In conclusion the writer desires to state that he would gladly 

 welcome suggestions from every source, whether these may dif- 

 fer from or conform to the views now expressed. For, if strength, 

 length of days, and needed leisure are granted him, he trusts 

 in future volumes to amplify and further extend present con- 

 clusions. 



Philadelphia, December, 1917. 



