ABSTRACTS OF TECHNICAL ARTICLES 1251 



netic behavior of the ferromagnetics. Perhaps it would have been more 

 logical to use the term Rochelle electrics, thus emphasizing the similarity in 

 the dielectric behavior to that of Rochelle salt, for which this behavior was 

 first discovered by J. Valasek. 



In this discussion the known ferroelectrics will be listed, and the various 

 theories that have been created to explain them will be examined. 



Theory of Ferroelectric Behavior of Barium Titanate. P. W. Anderson'. 

 References. Ceramic Age, v. 57, pp. 29-30, 33+, April, 1951. 



Criterion for Superconductivity. J. Bardeen^ Letter to the Editor. Phys. 

 Rev., V. 82, pp. 978-979, June 15, 1951. 



Magnetic Domain Patterns.* R. M. Bozorth^ Bibliography. //. de Phy- 

 sique, V. 12, pp. 308-321, March, 1951. 



Electron Temperature vs Noise Temperature in Low Pressure Mercury- Argon 

 Discharges. M. A. Easley' and W. W. Mumford^ Letter to the Editor. 

 //. Applied Phys.,v. 22, pp. 846-847, June, 1951. 



The Origin of Bombardment-Enhanced Thermionic Emission.* J. B. John- 

 SON^ References. Phys. Rev., v. 83, pp. 49-53, July 1, 1951. 



Abstract — Measurements on bombardment-enhanced thermionic emis- 

 sion from oxide cathodes show that (a) the effect is not related to normal 

 fading and recovery of thermionic emission; (b) the emitted electrons have 

 energies in the thermal range rather than in the secondary range. Calcula- 

 tions indicate that the electron bombardment releases more than enough 

 internal secondaries to account for the effect as increased thermionic emis- 

 sion. A more comprehensive theory is needed for explaining why the observed 

 effect is not even larger. 



Dipolar Domains in Paramagnetic Crystals at Low Temperatures. C. 

 KittellI. Letter to the Editor. Phys. Rev., v. 82, pp. 965-966, June 15, 1951. 



Methods of Measuring Adjacent-Band Radiation from Radio Transmitters.* 

 N. Lund'. I.R.E. Proc, v. 39, pp. 653-656, June, 1951. 



Abstract — A review of three possible methods of measuring or estimating 

 adjacent-band radiation characteristics of a radio transmitter is given. These 

 three methods differ in the type of signal applied to the transmitter and 

 may be termed the two-tone, normal signal, and thermal noise methods. 

 Measurements on a multichannel single-sideband transmitter using each of 

 these methods are presented to show that there is a good correlation between 

 the normal signal and thermal noise methods. 



An empirical method for calculating the slope of the adjacent-band radia- 

 tion as a function of frequency from the measured two-tone distortion values 



* A reprint of this article may be obtained on request. 

 1 Bell Tel. Labs. 



