100 Wheeler — L'ujht at Certain Metal-Liquid Surfaces. 



Discussion of the Results. 



An inspection of the tables just given shows that in the case 

 of each of the liquids examined n' — n„ within the limits of 

 error of the observations. In view of what has been said in 

 the introduction and in the discussion of the theory of the 

 experiments, this result indicates that there was present no 

 appreciable film or layer of any description ; and consequently, 

 for these liquids at least, the transition la} r er which has been 

 inferred from the phenomena of the reflection in air is not inde- 

 pendent of the medium with which it is in contact. In other 

 words, the transition layer is to be regarded as a true region of 

 interpenetration of two media ; and the fact that it is appreci- 

 able in liquids and not in solids must be attributed to the 

 greater freedom of molecular motions in the case of the former, 

 and not to any change in physical properties at the surface 

 brought about hy the force of surface tension. 



The liquids chosen for this investigation include those for 

 which the previous observations have yielded values of n' less 

 than n , and one for which a value of n' greater than n has 

 been found. As the result of this work goes to show that both 

 of these sorts of discrepancy vanish when all possible extrane- 

 ous films are removed, it would seem a fair inference that all 

 of the discrepancies which have been found previously are 

 to be attributed to the same causes, and that the conclusion 

 deduced from these experiments is a general one. 



Sheffield Scientific School of Yale University, 

 New Haven, Conn., April, 1911. 



