PREFACE ix 



of the old figures have been replaced and several additional 

 ones inserted. 



The bibliography appended to the book, which has been 

 considerably added to by Professor Wiedersheim since the third 

 German edition was published, is rather extensive for a work 

 of the kind, but I have not ventured to make selections from it 

 and have merely modified the arrangement in some respects and 

 made a few additions which seemed to me important for English 

 readers. It will, I trust, be found useful by more advanced students. 



I must acknowledge my obligations to my brother, Professor 

 T. Jeffery Parker, F.R.S., for numerous suggestions, and also 

 to Professor G. B. Howes, F.R.S., Mr. Frank J. Cole, and Mr. 

 Martin F. Woodward for valuable information on several special 



points. 



W. N. PARKEB. 



University College, Cardiff, 

 A2rril, 1897. 



