Decrease in the Paramagnetism of Palladium. 131 



predominated would largely depend on the portion of the 

 surface of the ball whence the nucleus was detached from. 



This interpretation seems to be confirmed by the following 

 experiments. When the iron ball was first placed in the 

 glass vessel and exposed for a short time to the emanation 

 which was introduced subsequently, a similar process gave a 

 normal result ; in all the haloes produced on a plate, the 

 relative numbers of the tracks of a rays from radium A and 

 radium C were the same. 



In conclusion, I wish to thank Professors Nagaoka and 

 Kinoshita for their kind interest in this experiment. I have 

 also to thank Professor Tawara of the Metallurgical De- 

 partment for his kindness in allowing me to use the 

 microphotographic apparatus. 



March 1916. 



JX. The Decrease in the Paramagnetism of Palladium 

 caused by Absorbed Hydrogen. By H. F. Biggs, B.A., 

 Assistant Lecturer in Mathematics in the University of 

 Manchester *. 



Contents. 

 I. Introductory. 

 II. Method. 



1. Principle of the Method. 



2. The Electromagnet and its Circuit. 



3. The Design of the Pole-pieces to give a constant Pondero- 



motive Force. 



4. The Torsion-system. 



5. Winding and Measurement of the Coils. 



6. Measurement of the Magnetic Force. 



7. Adjustment and Measurement of Balancing- Current. 

 III. Particulars of the Experiment on Palladium. 



References. 



(1) Graham. — Chemical and Physical Researches, p. 297. (Edin- 



burgh, 1876) ; Proc. Roy. Soc. xvii. 212, 500 (1869). 



(2) Cukie.— Ann. Chim. $ Phys. 7 ser. v. p. 350 (1895). 



(3) Honda.— Ann. d. Phys. xxxii. p. 1043 (1910). 



(4) Langevin. — Ann. Chim. fy Phys. 8 ser. v. p. 71 (1905). 



I. Introductory. 



PT1HE importance o£ determining the magnetic properties 



J- of hydrogen, whether in the form of molecules, atoms, 



or bare nuclei t, suggested a measurement o£ the effect of 



* Communicated by Sir Ernest Rutherford, F.R.S. 



t Hoitsema (Zeits. phys. Chem. xvii. p. 1, 1895) has shown that the 

 hydrogen in palladium is monatomic for small hydrogen-content. 



E. Newbery and the author made a rough experiment to see whether 

 the hydrogen given off from palladium carries a charge, but could 

 observe no such effect at pressures of a few hundredths of a millimetre 



K2 



