186 BELL SYSTEM TECHNICAL JOURNAL 



could be obtained by experimental studies of the transient coupling 

 between parallel earth-return circuits, free from the effects of shielding 

 conductors, and with concentrated, rather than distributed, grounds. 

 The study described in this paper was undertaken for this purpose. 



Energy of Lattice Distortion in Cold Worked Permalloy.^ F. E. 

 Haworth. The lattice distortion produced by severe cold working of 

 permalloy of 70 per cent Ni content has been studied by measuring the 

 broadening of the reflection of the Fe Ka doublet by the (311) planes, 

 with a focusing camera. The broadening decreases upon annealing 

 and recovery is complete at 650° C, when the breadth of the x-ray 

 intensity curve at half-maximum is as small as that obtained by use 

 of the two-crystal spectrometer. The mean square distortion in the 

 lattice spacing due to cold work is derived from the X-ray measurements 

 after photometering the x-ray film, converting the curve into an x-ray 

 intensity curve, fitting the latter with an empirical equation and using 

 an analysis worked out by S. O. Rice. The energy of the distortion 

 is then calculated by using an equation derived by G. R. Stibitz. The 

 root-mean-square distortion was found to be 0.31 per cent of the lattice 

 spacing after the material had been reduced 96 per cent in cross- 

 sectional area by cold working. The energy of distortion in the hard 

 worked condition is thus found to be 23 X 10® ergs/cm^ or 0.065 

 calorie/gram. 



Optical Constants of Rubidium and Cesium.'' Herbert E. Ives and 

 H. B. Briggs. In previous papers the authors have presented the 

 results of measurements of the optical constants of potassium and 

 sodium in the ultra-violet and visible ranges of the spectrum, with a 

 description of the apparatus used and the method of making measure- 

 ments. The present paper deals with the results of measurements of 

 the optical constants of rubidium and cesium by the same methods and 

 for the same wave-length range. As with sodium and potassium, 

 previous investigations of the optical constants of these metals were 

 confined to the visible region of the spectrum. 



The author's original interest in these constants lay in their applica- 

 tion to the theory of photoelectric emission from thin films. In order 

 to test this theory a knowledge of both the refractive index and the 

 extinction coefficient of the metals concerned is needed for the spectral 

 range embracing the characteristic photoelectric emission of the thin 

 films. The work described in this paper is intended to supply this 

 need. 



^ Phys. Rev., September 15, 1937. 



^ Jour. Opt. Soc. Amer., November 1937. 



