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. 



If the reader remember the name of the author of a paper on a 

 given subject, he will probably find it convenient to refer to the 

 Author Catalogue rather than to the Subject Catalogue. 



In the Author Catalogue the numbers placed within square brackets 

 at the end of each entry are Registration numbers, a,nd serve to 

 indicate the scope of each paper indexed. The meaning of these 

 numbers will at once be found by reference to the Schedule. 



In case the abbreviated titles of Journals are not understood, a key 

 to these is provided at the end of the volume. 



Topographical Symbols. 



In this volume geographical position is denoted by one or two letters 

 pi'inted in italics. The meaning of these symbols will be found in the 

 system of Topographical Classification which is printed in four languages 

 and placed between the Schedules and the Author Catalogue. Thus df 

 means " occurring in France " or " with reference to France." 



