viii PREFACE. 



volume must be looked upon only as a pioneer. If 

 1 have failed thoroughly to grasp its Philosophy, its 

 History, and its Purpose, may I at least be allowed 

 to claim the credit of honestly endeavouring to 

 rescue its mass of raw and tangled data from chaos, 

 and to reduce them to some kind of system and 

 Law. No one is more conscious than the author 

 himself of the little that has been done, and of the 

 amount of work that still remains to be accom- 

 plished ; but if the present effort forms a basis 

 for more elaborate study and detailed research, its 

 end and purpose will have been amply attained. 



Charles Dixon. 

 July, 1892. 



