322 BELL SYSTEM TECHNICAL JOURNAL 



includes those studies that have done most toward developing the basic 

 science of metals and alloys, and the latter includes technical develop- 

 ments and applications. 



Theory of Order for the Copper Gold Alloy System}^ W. Shockley. 

 The theory of order and disorder, in the form used by Bragg and 

 Williams, is extended to arbitrary composition of the constituent ele- 

 ments. The work is based upon the nearest neighbor interaction 

 assumption of Bethe and the connection between the Bethe and Bragg- 

 Williams theory is shown. In order to extend the Bragg-Williams 

 theory to compositions other than 25 and 50 atomic per cent, new 

 definitions of order are developed. The results are presented in terms 

 of phase diagrams and curves showing energy vs. temperature, specific 

 heat vs. temperature and state order vs. temperature. These results 

 are of importance in giving a general picture of the order-disorder 

 transformation for a wide composition range. They are not in detailed 

 accord with experiment due to the rather idealized picture underlying 

 the nearest neighbor assumption. 



A Theory of Noise for Electron Multipliers}^ W. Shockley and 

 J. R. Pierce. The noise in secondary-emission electron multipliers is 

 considered from a theoretical viewpoint. The noise properties of a 

 stage are correlated with its secondary-emission properties: the mean 

 value m and mean-square deviation 5^ of the number of secondaries per 

 primary. If /pA/ and /^a/ denote the mean-square noise current 

 lying in the frequency band A/ in the primary- and secondary-electron 

 currents, then 7sa/ = m^ ^pa/ + h'^lel^^ where /p is primary direct 

 current. This result is applied to many-stage multipliers. For n 

 similar stages 7,"I7 = MlPpA/ + h'^{_M{M - \)\m{jn - l)]2e/^ where 

 M = m" is the over-all gain of the multiplier. 



Wave Guides for Electrical Transmission}"^ G. C. Southworth. 

 The transmission of electric power at extremely high frequencies 

 through rods or "wires" of dielectric and through metal tubes, without 

 the usual return conductor, was predicted mathematically many years 

 ago. Recently experiments have confirmed this theory. Wave guides 

 offer the possibility of transmitting very wide frequency bands and 

 consequently extremely large numbers of speech channels without the 

 high attenuations encountered in radio; in fact, constantly decreasing 

 attenuation with increasing frequency is predicted for one type of wave. 



10 Jour. Chemical Physics, March 1938. 



11 Proc. I. R. E., March 1938. 



12 Elec. Engg., March 1938. 



