PRESSURE COEFFICIENTS OF CAPACITANCE 495 



V. SUMMARY 



Equations relating electrical capacitance and pressure have been 

 derived for plane capacitors under one dimensional and hydrostatic 

 pressures and cylindrical capacitors under radial pressure. The dielectric 

 material has been assumed to be an elastic solid but the relationships 

 also apply to fluid dielectrics when Poisson's ratio is set equal to ^. 

 Experiments corresponding to the assumptions have been described 

 briefly and experimental results are found to be in agreement with the 

 theoretical predictions. 



The results are of practical value in making estimates of the de- 

 pendence of attenuation of submarine cables on pressure. The equations 

 may also be put in forms useful for determining the dependence of the 

 dielectric constant on pressure from capacitance measurements. 



ACKNOWLEDGEMENT 



The author would like to acknowledge several valuable discussions 

 with G. T. Kohman and A. C. Lynch. Contributions to this work were 

 also made by A. W. Leber t and 0. D. Grismore. C. A. Weatherington 

 assisted in some of the measurements. J. A. Lewis made several impor- 

 tant comments on the manuscript. 



