OUR PRESENT KNOWLEDGE OF CANAL RAYS: A 

 DETAILED BIBLIOGRAPHY 



By GORDON SCOTT FULCHER 



Introduction 



My object in compiling the following collection and correlation 

 of the chief facts and theories regarding canal rays, as published 

 to date by various experimenters, is two-fold. 



First, it is hoped that the paper will prove valuable in itself. It 

 aims to be complete, to include all important phenomena discovered, 

 and to give exact references where details and methods may be 

 found. It should be an accurate map of the boundaries of knowl- 

 edge in this domain of Physics, and should prove suggestive to 

 research by indicating unexplored regions, and helpful to theorists 

 by containing the important phenomena to be explained and the 

 suggestions put forward by others. 



Second, it is hoped that the paper may illustrate the general 

 method well enough to commend its use by others in connection 

 with other branches of Physics, that these, too, may be mapped. 

 Every physicist would value greatly such a boiling down of the 

 literature in his field. 



In making the compilation, the articles were read as far as pos- 

 sible in chronological order, notes of facts reported being made on 

 cards and slipped into a card index under suitable heads. When 

 all the articles had been read, it was a simple matter to put together 

 the facts thus garnered. The method is perfectly flexible ; results 

 reported later can easily be incorporated. 



I shall be under deep obligation to any who will let me know of 

 buch mistakes or omissions as they may find in the following article. 



I am indebted to the authorities of Clark University for the privi- 

 lege of using their fine Physical Library. 



The subjects included in the present paper are arranged under 

 the followincf heads : 



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