All tests were run under continuous supervision. Readings 

 of all variables were taken every 15 minutes. Since both 

 control and test readings were made with the same instru- 

 ments, and the factors of interest were the differences 

 between these readings, no attempt was made to obtain 

 absolute calibration of the instruments. The estimated, 

 relative accuracy of the readings is given below: 



Pressure 

 Temperature 

 Voltage 

 Current 



± 500 psi 

 ± 1/4° F 

 ± 0.005 volt 

 ± 0. 05 ampere 



Figures 4 and 5 show the pressure equipment used during 

 laboratory tests. 



Figure 4. Pressure chamber used in tests, 



