ABSTRACTS OF TECHNICAL ARTICLES 491 



The noise measurements were made with equipment conforming to 

 the specifications described in the A. S. A. "Tentative Standards for 

 Sound Level Meters" (Z24. 3-1936), using the 40-decibel loudness- 

 weighting network. The measurements are expressed in terms of 

 sound level in decibels above reference sound level, that is, 10^^^ watt 

 per square centimeter at 1,000 cycles in a free progressive wave, each 

 measurement being based on the average of 50 individual readings. 



Electrical Conductance Measurements of Water Extracts of Textiles.^ 

 A. C. Walker. It has been shown that the electrical properties of 

 textiles depend upon chemical composition, water-soluble electrolytic 

 impurities, moisture content and manner of drying the material from 

 the wet state. Selection of a textile for electrical puposes should in- 

 clude consideration of the influence of chemical composition upon the 

 properties of the material, absence of significant amounts of electro- 

 lytes, and the method of drying the material from the wet state. 



This paper discusses the water extract conductivity method, its cor- 

 relation with insulation resistance data, and describes a simple, durable 

 electrolytic cell which is convenient to use for the conductivity meas- 

 urements. 



^A. S. T. M. Proc, Vol. 39, 1939. 



