ABSTRACTS OF TECHNICAL ARTICLES 607 



tempering experiments in which commercial high quahty tool steels 

 were used. Representative structures found in the quenched and 

 various tempered conditions are illustrated and discussed. 



Technique of the Talking Movie.^ Donald Mackenzie. In this 

 article the talking movies are described in some detail as to mechanical 

 features, production and exhibition. The author tells spme interesting 

 things about producing these pictures and the human reactions that 

 must be considered in preparing a picture with sound record so that it 

 will seem natural and the changes that producers will have to make to 

 satisfy the public. 



Some Long Distance Transmission Problems.^ H. Mouradian. 

 This paper discusses the transmission properties of high voltage power 

 transmission lines with incidental reference to telephone transmission. 

 The method of improving the performance of power lines by means of 

 synchronous condensers at the ends and at intermediate points is 

 discussed and compared with a proposed method in which neutralizing 

 networks are neutralized at intervals. Each network consists of a pi 

 whose series and shunt elements neutralize the corresponding elements 

 of the line at the frequency of transmission. It is stated that the 

 synchronous condensers increase the power transfer limits of the line 

 but decrease the transmission efficiency, while the neutralizing net- 

 works increase both the power transfer limits and the efficiency. 

 Illustrative numerical examples are given for a 220,000-volt line, 500 

 miles long. Some possibilities of a transcontinental power transmission 

 line are discussed. 



Electrical Conduction in Textiles. Part II — Alternating Current 

 Conduction}^ E. J. Murphy. This paper shows the variation of the 

 equivalent parallel capacity and conductance of cotton and silk with 

 relative humidity and frequency (for a small range). It also shows the 

 effect of changes in the amount of electrolytic material in the textile. 

 The main results are: At high humidities the capacity is greatly 

 reduced by a reduction in the amount of electrolytic material in the 

 textile. The a.c. and d.c. conductivities of cotton approach each other 

 as the humidity is increased and become equal at humidities greater 

 than 80-85 per cent (that is, dielectric loss is entirely due to direct 

 current conductivity in this range). At humidities lower than this a 

 large part of the dielectric loss is not due to d.c. conduction, but this 



* Journal of the Western Society of Engineers, Vol. 34, February, 1929, pp. 95-102. 

 8 Journal of the Franklin Institute, Vol. 207, February, 1929, pp. 165-192. 

 ^'^ Journal of Physical Chemistry, Vol. H, February, 1929, pp. 200-215. 



