1890.] 



recently formed Liquid Surfaces. 



285 



all cases the sharpness of the resulting photographs is evidence that 

 the sixth contact was properly made, and thus that the scale of 

 magnification was strictly preserved. Fig. 3 is a reproduction on the 



Fig. 3. 



original scale of a "photograph of a water jet taken upon 9th Novem- 

 ber. The distance recorded as 2\ is between the points marked A 

 and B, and was of course measured upon the original negative. On 

 each occasion when various liquids were under investigation, the 

 photography of the water jet was repeated, and the results agreed 

 well. 



After these explanations it will suffice to summarise the actual 

 measurements upon oleate of soda in tabular form. The standard 

 solution contained 1 part of oleate in 40 parts of water, and was 

 diluted as occasion required.* All lengths are given in millimetres. 





Water. 



Oleate 



Oleate 



Oleate 



Oleate 







1/40. 



1/80. 



1/400. 



1/4000. 



2a , . . , 



40-0 



45-5 



44 



39 -0 



39 -0 



h 



31-5 



11 -o 



■ 



11-0 



11 



23 



In the second row h is the rise of the liquid in a capillary tube, 

 carefully cleaned before each trial with strong sulphuric acid and 

 copious washing. In the last case, relating to oleate solution 4^00", 

 the motion was sluggish and the capillary height but ill-defined. It 

 will be seen that even when the capillary height is not much more 

 than one-third of that of water, the wave-lengths differ but little, 

 indicating that, at any rate, the greater part of the lowering of 



* Although I can find no note of the fact, I think I am right in saying that large 

 bubbles could be blown with the "weakest of the solutions experimented upon. 



