xii TABLE OF CONTENTS 



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ON THE DISPERSION OF " N " RAYS, AND ON THEIR 

 WAVE-LENGTH 53 



ON THE PHOTOGRAPHIC REGISTERING OF THE ACTION 

 PRODUCED BY " N " RAYS ON A SMALL ELECTRIC 

 SPARK 61 



ON A NEW SPECIES OF " N " RAYS 68 



ON PECULIARITIES PRESENTED BY THE ACTION WHICH 



"N" RAYS EXERCISE UPON A DIMLY LIGHTED 



SURFACE 72 



ON THE COMPARATIVE ACTION OF HEAT AND " N " 



RAYS ON PHOSPHORESCENCE 74 



COMPLEMENTARY NOTES 77 



INSTRUCTIONS FOR MAKING PHOSPHORESCENT SCREENS 



SUITABLE FOR THE OBSERVATION OF " N " RAYS 79 

 How THE ACTION OF "N" RAYS OUGHT TO BE 



OBSERVED . 82 



