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L. On the Capillary Phenomena of the common Surface of two 

 Liquids, By G. Quincke. 



[Continued from p. 266.] 



II. Flat drops or bubbles coated with heterogeneous liquids. 



11. TF on a flat drop of a liquid 1 of large diameter 2r, which 

 J- is on a horizontal glass plane in a liquid 2, a small drop 

 of another liquid, 3, is placed, and this small drop of liquid 3 

 spreads itself out on the common surface of liquids 1 and 2*, 

 then it coats this with a thin layer or film of extremely small 

 thickness. It may then be assumed that the form of the 

 common surface of liquids 1 and 3 is the same as that of the 

 common surface of liquids 2 and 3. 



The equations of § 3 will still hold good under this supposi- 

 tion, if « 13 + a 32 be introduced instead of the constant a 12 . We 

 have 



« = ^ ^L^=a 13 + « 32 , . . . (5a) 



K— &=a, (8a) 



K = a \/l — cosa>; (9a) 



and for the case in which the angle o) = 180°, 



K=a\/2 (10a) 



In the following Tables, analogously to the earlier notation (§ 8), 

 we have 



a=(K-*) 2 



- K 2 



(14a) 



In this calculation the thickness of the layer of the liquid 3 is 

 assumed to be less than the length (which can still be deter- 

 mined at K or k), consequently somewhat less than O'Ol millim. 

 But, on the other hand, this thickness is also presupposed 

 > 21, greater than twice the distance at which the molecular 

 forces of capillarity are still effective. 



12. In the first place, air may be taken as liquid 1, an air- 

 bubble being blown in a liquid 2 under a horizontal glass 

 plane in the manner described in § 5. A small drop of sub- 

 stance 3 is introduced, by means of a tube bent at right angles, 

 on the surface of the air-bubble in liquid 2, where it spreads 

 itself out. 



* As to the conditions on which this result depends, compare Section V. 

 §§ 24-32. 



