772 the bell system technical journal, may 1953 



Luke, C. L.^ 

 Photometric Determination of Silicon in Ferrous, Ferromagnetic, 

 Nickel, and Copper Alloys — A Molybdenum Blue Method, Anal. 

 Chem., 25, pp. 118-151, Jan., 1952. 



A simple, rapid photometric method for the determination of siHcon in fer- 

 rous, ferromagnetic, nickel, and copper alloys has been developed. Wide 

 applicability is its most unique and important feature. Interfering elements are 

 removed by a carbamate-chloroform extraction and siUcon is then deter- 

 mined by the photometric molybdenum blue method. Confirmatory data on 

 a wide variety of samples of known silicon content are presented. 



LUMSDEN, G. Q.^ 



A Quarter Century of Evaluating Pole Preservatives. Amer. Wood 

 Preservers' Assoc, Proc, 48, pp. 27-47, 1952 (Monograph 1999). 



Mac Williams, W. H., Jr.^ 



Computers — Past, Present, and Future, Elec. Eng., 72, pp. 116-121, 

 Feb., 1953. 



This article deals with the historical development of computers. It also dis- 

 cusses current problems and indicates future structural and functional com- 

 puter trends which will help to free man from burdensome calculations and 

 increase his material wealth while permitting him more time for pursuits 

 not directly concerned with earning a living. 



Miller, R. L., see W. E. Koch. 



MUMFORD, W. W.^ 

 Optimum Piston Position for Wide-Band Coaxial-to -Waveguide 

 Transducers^ I.R.E., Proc, 41, pp. 256-261, Feb., 1953. 

 A coaxial line can be matched to a waveguide by means of a probe antenna 

 located ahead of a short-circuiting plunger. An impedance match can usually 

 be achieved by varying any two of the following three dimensions: (a) the 

 off-center position of the probe, (b) the probe length, (c) the piston position. 

 This paper points out that there is, theoretically, an optimum piston position 

 for greatest bandwidth, and presents some evidence corroborating this theory. 

 Bandwidths greater than ±10 per cent to the 1 db swr points have been 

 realized by fixing the piston at its optimum position and varying (a) and (b) 

 above to obtain a match. 



Nelson, R. A.,* and W. Band* 

 Vapor Pressure of He' = He* Mixtures, Letter to the Editor, Phys. 

 Rev., eSr p. 1431, Dec. 15, 1952. 



* Bell Telephone Laboratories. Inc. 



' American Telephone and Telegraph Company. 



* State College of Washington. 



