466 BELL SYSTEM TECHNICAL JOURNAL 



faming Germanium and Radioactive Antimony 124* G. L. Pearson/ J. D. 

 Struthers,^ and H. C\ Theurer.' Pliys. Rev., V. 77, pp. 809-813, March 

 15, 1950. 



Optical Method for Measuring the Stress in Glass Bulbs* W. T. Read.^ 

 Applied Phys., Jl., V. 21, pp. 250-257, March, 1950. 



Programming a Computer for Playing Chess. C. E. Shannon.^ References. 

 Phil. Mag., V. 41, pp. 256-275, March, 1950. 



Abstract — This paper is concerned with the problem of constructing a 

 program for a modern electronic computer of the EDVAC type which will 

 enable it to play chess. Although perhaps of no practical importance the 

 question is of theoretical interest, and it is hoped that a satisfactory solution 

 of this problem will act as a kind of wedge in attacking other problems of a 

 similar nature and of greater significance. 



Recent Developments in Communication Theory. C. E. Sh.a.nnon.^ Elec- 

 tronics, V. 32, pp. 80-83, April, 1950. 



Abstract — In this paper the highlights of this recent work will be de- 

 scribed with as little mathematics as possible. Since the subject is essentially 

 a mathematical one, this necessitates a sacrifice of rigor; for more precise 

 treatments the reader may consult the references. 



A Symmetrical Notation for X umbers. C. E. Shannon.^ .-Iw. Math. Monthly, 

 V. 57, pp. 90-93, February, 1950. 



Capacity of a Pair of Insulated ]]'ires.* W. H. Wise.^ Quart. Applied 

 Math., V. 7, pp. 432-436, January, 1950. 



Echoes in Transmission at 450 Megacycles from Land-to-Car Radio Units.* 

 W. R. Young, Jr.' and L. Y. Lacy.' I.R.E., Proc, \. 38, pp. 255-258, 

 March, 1950. 



Simplified Derivation of Linear Least Square Smoothing and Prediction 

 Theory.* H. W. Bode' and C. E. Shannon.' LR.E., Proc, \. 38, pp. 417- 

 425, April, 1950. 



Abstract — In this paper the chief results of smoothing theory will be 

 developed by a new method which, while not as rigorous or general as the 

 methods of Wiener and Kohnogoroff, has the advantage of greater simplic- 

 ity, particularly for readers with a background of electric circuit theory. 

 The mathematical steps in the present derivation have, for the most part, 

 a direct i)hysical interi)retation, which enables one to see intuitively what 

 the mathematics is doing. 



Helix Parameters Used in Traveling Wave-Tube Theory.* R. C Fletcher.^ 

 LR.E., Proc, V. 38, pp. 413-417, April, 1950. 



Abstr.act — Helix parameters used in the normal mode solution of the 

 traveling-wave tube are evaluated by comparison with the field equations 



*A reprint of this article inav l)c obtained <>n request to the editor of the B. S.T.J. 

 'B.T.L. 



