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INSTRUCTIONS. 



The present volume consists of three parts : — 



(a) Schedules and Indexes in four languages. 

 {h) An Authors' Catalogue, 

 (c) A Subject Catalogue. 



The Subject Catalogue is divided into sections, each of which is 

 denoted by a four-figure number between 0000 and 9999. These 

 numbers follow one another in numerical order, but all the 9999 

 numbers are not used, for it is intended to fill up the gaps by interpola- 

 tion of such additional sections as may be required for additions to the 

 system of classification in future ^-ears. 



To enable the reader to find these numbers quickly, the first or last 

 number on the pagei s repeated at the head of the page. In looking 

 up a subject, these numl3ers, which are called Registration numbers, 

 should be used instead of the ordinary pagination. These Registration 

 numbers serve to divide up the subject into sections, each of which 

 deals with related matter. 



In each section the final an-angement of papers is in the 

 alphabetical order of authors' names. 



In order to find the papers dealing' with a particular subject the 

 reader may either consult the Schedule or the Index to the Schedule. 

 The numbers given in the index are Registration numbers, and can be 

 used at once for turning to the proper page of the Subject Index. This 

 is done by looking at the numbers at the top corners of the pages. 



