[ 33 ] 
IT. The j\[eamrement of Magnetic Hysteresis. 
By G. F. C. Searle, M.A., Peterhousc, University Lecturer in Physics, and 
T. G. Bedford, M.A., Sidney Sussex College, Demonstrators at the Cavendish 
Lahoratory, Ca m hridge. 
Coninmnicated hy Professor J. J. Thomson, F.R.S. 
Received May 2,—Read June 6, 1901. 
Section 
1- 3. 
4- 6. 
7-12. 
1.3-1.5. 
16-20. 
21-3.0. 
36-37. 
38-41. 
42. 
43-4.5. 
46-49. 
50. 
51-52. 
53-58. 
59-61. 
62. 
63. 
64-69. 
70. 
71. 
Contents. 
Rage 
Introduction. 
Approximate Theory of the Authors’ Method of Measuring jMagnetic 
Hysteresis. 
Complete Theory of the Method. 
Determination of the Correction for the Finite Conductivity of the 
Secondary Circmt, and of the Energy dissipated by Eddy Currents . 
Application of the Method to Rods of Finite Length. 
Description of the Apjoaratus. 
Practical Example of the Method. 
Tests of the Accuracy of the Method. 
Energy dissipated by Ivldy Currents. 
Complete Cycles and Semi-cycles. 
Effect of Continued Reversals. 
W-Ra Curves for Zero Stress. 
34 
37 
40 
46 
49 
52 
61 
62 
66 
68 
70 
Effect of Tension.73 
Effect of Torsion within the Elastic Limit.75 
Effect of Tor.sion beyond the Ela.stic Limit.82 
Influence of Permanent Set upon the Effects of Cycles of Torsion . . . 85 
Development of a CVclic State after Initial Permanent Set.87 
Relation connecting AV with By and II„.89 
Effect of an Electric Curi'ent upon Hysteresis.93 
Conclusion. 94 
ArrEXDix I. 
72-73. On the Heat produced l>y Eddy Currents in Rods of Circular and Rect¬ 
angular [and Elliptical] Sections. 96 
Appendix II. 
74-79. On the Demagnetising Force due to Rods of Finite Length . . . .98 
VOL. CXCVIII.— A 301. F 31.1.1902 
