124 



PROCEEDINGS OF THE AMERICAN ACADEMY, 



Apparatus and Method of Procedure. 



Figure 1 shows diagrammatically the general arrangement of the 

 great array of apparatus used in making the measurements described 

 m this paper. This apparatus was adjusted and some of it constructed 



Figure 1. This Figure shows diagrammatically the general arrangement of 

 some ot the apparatus used in making the observations described in this 

 FoTT" It ^ ^^^*® devices for demagnetizing the specimens are omitted 



by Mr. John Coulson of the scientific staff of the Jefferson Laborator;^-, 

 who has worked with me at every stage of the investigation, and to 

 whose skill and patience I am deeply indebted. Many details are 

 omitted from the figure. The devices for demagnetizing the speci- 

 mens to be tested will be described later on. 



