Vi PREFACE, 



1898. The inconvenience of the delay in publication is obvious. The 

 contributors see other writers secure the priority of their work, while 

 the manuscript has continually to be re-written to incorporate what has 

 been published while it is waiting for the printer. For all this I am in 

 no way responsible. I prepare the work ; but over printing and publi- 

 cation I have not the slightest control. And as no less then five 

 government departments have a say in the matter, the task of getting 

 them into line is one of no small difficulty. A fire which took place 

 at the printer's in December of last year was a further impediment. 

 Fortunately, however, most of the manuscript was recovered eventually 

 from the ruins. 



Three more volumes will complete the work as originally planned. 

 Their preparation presents no inherent difficulty, but their fate lies on 

 the lap of the gods. 



I must again record my acknowledgements of the assistance given 

 me by Mr. C. H. Wright in preparing the manuscript for the press and 

 in checking the proofs, and to Mr. N. E. Brown for working out the 

 geographical distribution. 



W. T. T. D. 



Kew, November 1900. 



