228 Linebarger — Tension of Mixtures of Normal Liquids. 



Table VI. 

 Surface Tension of Mixtures of Ethyl Oxide and Ethyl Iodide. 



Temperature 25° 

 Molpcular Observed Calculated 



Percentage Percentage Specific Surf nee Surface Differ- 



Composition. Composition. Gravity. Tension. Tension, ences. 



C4010O C2H5I C4H10O C2II5I 



0.000 100.000 0.000 100.000 1.93012 29.49 

 37.200 62.800 55.581 44.419 1.T7996 20.57 19.13 —1.44 

 100.000 0.000 100.000 0.000 0.70942 16.35 



Table VII. 



Surface Tension of Mixtures of Ethyl Oxide and Carbon Bisul- 

 phide. 



Temperatu'-e 25° 

 Molecular Observed Calculated 



Percentage Percentage Specific Surface Surface Differ- 



Composition, Composition. Gravity. Tension. Tension. ences. 



C.HioO CS2 C4HJ0O CS2 



0.000 100.000 0.000 100.000 1.25958 31.29 



13.100 86.900 13.407 86.593 1.14280 26.19 29.61 +3.42 



34.367 65.633 34.969 65.031 0.99380 21.86 26.16 4-4.30 



62.759 37.241 63.380 36.620 0.84699 18.65 21.91 +3.26 



100.000 0.000 100.000 0.000 0.70942 16.35 



The results communicated in the foregoing tables show that 

 in the majority of cases the superficial tensions of mixtures of 

 normal liquids are not calculable by the rule of mixtures from 

 the superficial tensions of the pure liquids. Mixtures of ben- 

 zene and toluene show differences between the calculated and 

 observed values of their surface tensions that are less than 

 those attributable to experimental errors. Yet it must be 

 borne in mind that the method of determination does not yield 

 results that are accurate on an average to more than one part 

 in a thousand, and it is quite permissible to believe that more 

 accurate experimental methods will show marked differences 

 between the calculated and observed values of the -physical con- 

 stant under discussion. 



It is to be observed that there are no abrupt changes in the 

 capillary constants of any of the mixtures, that is to say, if the 

 observed value is greater or less than the calculated value for 

 any one mixture of two liquids, it is also greater or less for any 

 other mixture of the same two liquids ; the signs before the 

 numbers in the column marked ^' Differences " remains the 

 same for every series of mixtures. 



