ABSTRACTS OF TECHNICAL ARTICLES 1255 



scut back to the ciuartz crystal which serves as both transinittei' and receiver. 

 Tlie phase shift and added attenuation caused by immersing the rod in the test 

 liciuid are measiu'cd by means of a special balancing ari-angement, and yield a 

 calculation of the impedance presented to the rod surface. From an analysis of 

 wave propagation both in the rod and in the liciuid, one can calculate the charac- 

 teristic siiear impedance of the liciuid, and the dynamic vis('osity and stitTness. 

 I )ata for polyisobutylene liquids with static viscosities up to 2000 i)oises are 

 given for the frecjuency range 25-1 oO kc. High freijuency data (5 2") mc) for the 

 same liciuids obtained by a method previously rei)orted on (see reference 10 (b)) 

 are correlated to the present work. Some results for polypropylene, polyisoprene, 

 polybutadiene, and polypropylene sebacate are also given. 



New Transistors Give Improved Fcrfonnnnee. J. A. Morton . Electron- 

 ics, 25, pp. 100-103, August, 1952. 



Better manufacturing processes and germaiiium materials have provided 

 greater reliability and reproducibihty and improved frequency response. Higher 

 power output and better noise figure for high-sensitivity applications are proper- 

 ties of new types. 



Microwaves. J. R. Pierce\ *Sa. Am., 187, pp. 43-51, August, 1952. 



They are radio waves that range in length from about a quarter of an inch to 

 two feet. Investigated during the war for their utility in radar, they are now 

 widely applied in communication. 



Glass Unit for Liquid and Vapor Phase Extraction Employing a Single 

 Processing Chamber. H. A. Sauer^ Anal. Chem., 24, p. 1232, July, 1952. 



The Transistors Development Status at Bell Telephone Laboratories, 

 with Demonstration. W. R. Sittner\ pp. 138-142. A. I. E. E., I. R. E. 

 and R. T. M. A. Symposium, Progress in Quality Electron Components. 

 Proceedings, Wash., D. C, May 5-7, 1952. Wash., D. C, R. T. M. A., 

 1952. 



Polyethylene Terephthalate as a Capacitor Dielectric. M. C. Wooley\ 

 G. T. KoHMAN^ and W. McMahon^ Elec. Eng., 71, pp. 715-717, Aug., 

 1952. 



Polyethylene terephthalate, or "Mylar", is a new rival of paper for use as the 

 dielectric in electric capacitors. It appears superior in regard to insulation 

 resistance, temperature coefficient of capacitance, and operating temperature 

 range. 



'Bell Telephone Laboratories 



