.mSTR.-tCTS OF BULL SiSTLM ll.CIIMC.IL r.ll'LKS 511 



sample itself is l>.il.iiu'e(l l)>' passing a measured current tliroii^;li a 

 third roil. The apjilied field and the induced ni.igneti/atiun are then 

 proportional to the electric currents passeil through the magnetizing 

 coil and the balancing coil, respectively. A hysteres s loop is shown, 

 ohiained from an iron wire weighing '.i mg. 



An Ex f>Ui nation of Peculiar Reflections Obsenrd on X-Ruy Powder 

 Photoi^raphs* Richard M. Bozorth. There has been pre\iously 

 reportcti (J. O. S. A. and R. S. I. 0,989-97; 1922) the existence of 

 "anotnalous" retleclions of X-rays, observed when analyzing sub- 

 stances by the melh(xi of Dcbye-Scherrer and Hull. These reflec- 

 tions are now explained in accordance with the well-known laws 

 governing X-ray rellections. It is shown that the molybdenum X-ray 

 spectrum as ordinariK- used, although it is filtered by zirconium 

 screens, contains in addition to the characteristic Ka radiation a 

 considerable amount of general radiation. Although usually not 

 effective, this general radiation becomes important when the sample 

 iR-ing analyzed is composed of crystal grains of certain sizes. The 

 etTect under di.scussion is caused by reflection of this general radiation 

 trom the principal atom planes of these crystals. Several experiments, 

 and a geometrical analysis of the positions and orientations of the 

 difTraction effects, confirm this conclusion. 

 •J. O. S. A. and R. S. I. 9, 123-7 (August, 1924). 



