DAVIS. — THE LAW OF CORRESPONDING STATES. 263 



tests. The corrections in the tests summarized in Table IV averaged 

 2.4° F., and only occasionally amounted to 4°. Those in the tests 

 summarized in Table V averaged 2.9° F. and only occasionally 

 amounted to 5°. 



The second set of corrections which are involved in Table V but not 

 in Table IV are much more uncertain. As has been stated, the ex- 

 periments of the runs of Table V could not be grouped into throttling 

 curves whose various low side points could be combined with each 

 other, all the high side observations being ignored except as indicating 

 constancy of initial conditions, as was done in preparing Table IV. If 

 the data were to be used at all, each low side point had to be taken 

 with its own high side point. When this was done with only the 

 radiation and conduction corrections made, the resulting values of the 

 Joule-Thomson coefficient were not at all self-consistent, the values in 

 each run which corresponded to small temperature drops and therefore 

 to high mean temperatures being abnormally high. This tendency of 

 the points near 0.9 in Figure 6 to swoop upward was unmistakable, and 

 indicated clearly the presence in the tests of Table V of the same " wet 

 steam " error shown in Figure 5 for the tests of Table IV. 



The necessary corrections were obtained from the tests of Table IV. 

 It seemed that they alone gave enough of a verification of the law 

 of corresponding states to justify the drawing of a tentative curve like 

 those of Figure 7, and this curve was then used to compute what 

 correction would have to be applied to each of the high side tempera- 

 tures of the tests of Table IV to make them self-consistent. These 

 corrections were surprisingly constant. They were examined for 

 systematic variations with mean pressure, with pressure drop and with 

 quantity of steam discharged, without success. There seemed, how- 

 ever, to be a slight variation with the mean temperature and the 

 following scheme was adopted : 



If the mean reduced decrease the high 



temperature is side temperature by 



0.9 14° 



0.85 13° 



0.8 12° 



0.75 11° 



It should be noticed that these corrections were deduced wholly 

 from the 14 throttling curve tests of Table IV. When they were 

 applied to the tests of Table V, the resulting values of the coefficient 

 showed none of their previous tendency to run high near 0.9, and were 



