Experiments on Polarized Rontgen Radiation. 801 



absorbing substance, it might be expected that there would 

 be a considerable alteration in the absorption of the material. 

 With such an idea in mind, the following experiment was 

 tried. 



A polarized beam of X-rays was passed through iron when 

 unmagnetized, and later when magnetized. The absorption 

 of the polarized beam was determined in each case. In the 

 first experiment, the field produced was perpendicular to the 

 sheet of iron absorbing and parallel to the direction of the 

 X-rays absorbed. In the second part the field was per- 

 pendicular to the direction of the X-rays absorbed and parallel 

 to the sheet of iron absorbing. The field was produced in 

 the first instance by a coil of wire, and in the second case 

 by a powerful horseshoe electromagnet. In each case a 

 standardizing electroscope was emploj^ed to allow for changes 

 in the primary beam. 



The results are given in tabular form. 



Magnetic field perpendicular to X-rays and 

 parallel to iron sheet. 



H = 30,000 gauss. 



Absorption "by iron Absorption by iron 



unmagnetized. magnetized. 



68*0 per cent. 68*0 per cent. 



67-2 „ 67-0 



20-1 „ 20-3 „ 



20-5 „ 20-1 „ 



Magnetic field parallel to X-rays and perpendicular 

 to iron sheet. 



H = 320 gauss. 



Absorption by iron Absorption by iro 



unmagnetized. magnetized. 



53*0 per cent. 53*1 per cent. 



31*7 „ 31*0 



31*7 „ 32-4 



31*8 „ 31-9 



Thus the absorption of a polarized beam of X-rays by iron 

 is not appreciably dependent upon whether it is magnetized 

 or unmagnetized ; that is, absorption of X-rays is independent 

 of the orientation of the electronic orbits inside the atom, so 

 far as they are affected by the magnetic state. 



