PREFACE TO VOLUME XII. 



In the Preface to Volume IX. of the Royal Society's Catalogue of Scientific 

 Papers, which was the first of the three volumes forming the Third Series, it 

 was stated that the President and Council had it in contemplation to issue 

 a Supplementally Volume in which would be catalogued all the most important 

 papers that had appeared from 1800 to 1883 in periodicals not hitherto 

 indexed. 



In pursuance of the intention then expressed the Supplementary Volume 

 now issued has been compiled, though it must be confessed that the work 

 involved in its compilation has far exceeded what was originally contemplated. 

 After a careful sifting of a preliminary list of periodicals not previously 

 catalogued it was found that upwards of three hundred and fifty serials 

 remained to be dealt with. A list of these, many of which were by no means 

 easy of access, together with the abbreviated references adopted, is prefixed to 

 this volume. 



A few modifications have been introduced in the method of compilation, 

 which cause the present volume to vary in some respects from those previously 

 issued. The principal of these are : 



(1) No references are given to papers already referred to in previous 

 volumes, except in cases where such previous references were to mere abstracts 

 or less complete versions of the paper. 



(2) All references to abstracts of papers have been excluded, except in 

 the case of papers in some other language than English, French, German, Italian 

 or Latin, abstracts of which have been published in one of these languages. In 

 such cases a reference to one abstract has been printed. 



(3) In the case of Hungarian, Czech, Polish and Russian titles, trans- 

 lations have been printed, except when the title has already appeared in a 

 previous volume of the Catalogue accompanied by a translation. 



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