XI 



In the Authors' Catalogue each title is given in the original 

 language. When, however, that language is not one of the five 

 above mentioned, a translation into one of these five languages is 

 added. In such cases the actual title is printed first, and is followed 

 by the translation within square brackets. 



It was provided by the original scheme that the Catalogue should 

 comprise all original contributions to the branches of science which 

 come within its scope, whether these had been published in periodicals, 

 or in the journals of societies, or as independent pamphlets, memoirs, 

 or books. 



In order that a scientific investigator might be in a position to 

 ascertain by means of the Catalogue what has from time to time been 

 published concerning each particular subject of inquiry, it was held to 

 be of great importance that not only the titles of papers but their subject 

 matter also should be indexed. As stated above, however, financial 

 considerations have led to the number of subject-entries being at 

 present limited in number. But the expense of making subject-entries 

 would be ver^^ greatly reduced if all periodicals adopted a practice 

 already carried out by some journals, namely, that of indexing each 

 paper at the time of its publication. Indeed, were this carefully done, 

 the Bureaus preparing the Catalogue would no longer have to study 

 the contents of papers in order to prepare the subject-entiies. and the 

 saving thereby effected would make it possible to enlarge the scope 

 of the Catalogue, until it include all original scientific communications. 

 Seeing how necessary such a complete subject catalogue is for the 

 progress of science, it is hoped that all editors and authors will 

 co-operate in so preparing subject-indexes for all papers at the time 

 of their publication. 



