180 BELL SYSTEM TECHNICAL JOURNAL 



rubber-sulfur vulcanization. The results offer further insight into the vul- 

 canization problem. The products of the reaction are liquids of the polysul- 

 fide type R-Sx-R, where x varies from 2 to 6 and R is an alkyl or alkenyl 

 group and two solids (CsHcSs and a higher homolog). The polysuliides ap- 

 pear to be somewhat richer in hydrogen than is expected from reaction of 

 two CsHio molecules, whereas the solids are hydrogen-poor. The structure 

 of an acid anhydride in the sulfur system showing thione-thiol tautomerism 

 is proposed for CsHeSs, which is therefore 2 , 5-dithione-3-methyltetrahy- 

 drothiophene. ■ The color changes with reaction time, from yellow to red to 

 black, parallel those of rubber-sulfur vulcanizates. As in rubber-sulfur 

 vulcanization the sulfur reaction rate is directly proportional to time, al- 

 though the absolute rate is twice that in the polymer system. Starting with 

 equal mole quantities of olefin and sulfur, there is a considerable amount of 

 unreacted olefin in the system when all of the sulfur has reacted. The 

 shorter the reaction time, the higher the value of x in the polysulfide 

 R-Sx-R and the larger the percentage of residues R that are saturated. 



On Hearing in Water vs. Hearing in Air}'' L. J. Sivian. The paper deals 

 with the ability of a submerged listener to hear sounds generated in the air 

 above him, compared with their audibility when his head projects above the 

 water. In a theoretical discussion it is shown that at 1000 c.p.s. a loss of 

 the order of 45-55 db might be expected in the in-water audibility relative to 

 the in-air value. This involves a number of assumptions, e.g., that there is 

 no appreciable noise created by the listener's propulsion, and that the effect 

 of hydrostatic pressure unbalance on the eardrum is negligible. A few 

 measurements made at 1000 c.p.s. and 3000 c.p.s. yielded values which are 

 not at variance with the theoretical analysis. 



Cathode Phase Inverter Design}^ C. W. Vadersen. Part I of this paper 

 covers the general analysis of the cathode coupled phase inverter and de- 

 velops formulae that enable the designer to compute circuit elements with 

 good accuracy. The theory developed shows that degeneration exists only 

 in the driven side of the amplifier and is limited to 6 decibels. Balance is 

 discussed in terms of the tube parameters and external resistances, its being 

 shown that considerable stability is attainable. A form of the inverter in 

 which the power output stage utilizes a transformer with an unbalanced 

 plate winding is presented. This is shown to give a true power balance in a 

 manner analogous to the unbalanced plate resistor form of the voltage 

 amplifying inverter. 



Part II presents a graph of the general design equations and illustrates its 

 use with several working examples. 



" Jour. Acous. Soc. Amer., May 1947. 

 ^* Audio Engineering, June and July 1947. 



