902 BELL SYSTEM TECHNICAL JOURNAL 



series of standards are excited in the direct current arc, and their spectra 

 recorded on the same plate. Determinations of the amounts of constituent 

 elements present in the sample are made by measuring the logarithm of the 

 ratio of the relative intensities of a line of the element sought to that of a 

 nickel control line by the general internal control technique. 



Measurement of the Viscosity and Shear Elasticity of Liquids by Means of a 

 Torsionally Vibrating Crystal.^ W. P. Mason. This paper describes a 

 method of measuring viscosities of liquids at high frequencies by means of 

 oscillating cylinders, in which a torsionally vibrating crystal generates a 

 viscous wave in the medium to be measured. Both a reactance and a resist- 

 ance loading occur in the crystal which lowers its frequency and raises the 

 measured resistance at resonance. The viscosity may then be determined 

 by measuring the changes in the properties of the crystal. By varying the 

 voltage on the crystal, the shearing displacement can be varied and hence 

 the viscosity can be measured as a function of shearing stress. Measure- 

 ments on light oils over a viscosity range from 0.01 poise to 10 poises check 

 within a few per cent when made with rough temperature-control conditions. 



Considerations in the Design of Centimeter-Wave Radar Receivers.^ Stew- 

 art E. Miller. A review of the radar duplexer and receiver, as developed 

 during the war, is presented. Attention is devoted to the principles of oper- 

 ation and typical circuit arrangements employed in the duplexer, the crystal 

 converter, the local-oscillator injection circuits, the intermediate-frequency 

 amplifier, and the automatic-tuning unit. Emphasis is placed on methods 

 found advantageous in the 1 -centimeter and 3-centimeter wavelength re- 

 gions. The interrelation between the various receiver components in deter- 

 mining the over-all receiver noise figure is shown analytically, and typical 

 performance numbers are given. 



Experimental Rural Radiotelephony}^ J. Harold Moore, Paul K. 

 Seyler and S. B. Wright. The first rural party-line telephone service 

 utilizing radio installations operating on the subscribers' premises was under- 

 taken experimentally in the vicinity of Cheyenne Wells, near the eastern 

 border of Colorado. Radio links have been used to supply regular telephone 

 service to eight ranches since August 20, 1946. The development of a 

 standard rural radiotelephone system will be aided materially by the expe- 

 rience gained from these experiments. 



8 Transactions A.S.M.E., May 1947. 



^Froc.LK.E., April 1947. 



'° Electrical Engineering, April 1947. 



