﻿of the common Surface of two Liquids. 



469 



Draparnaud*. 



Water. 



Alcohol. 



Water. 

 Volatile oil. 



Olive-oil. 

 Spirits of wine. 



Water. 



Oil of turpentine. 



Water. 

 Alcohol. 



Water. 

 Ether. 



Carradori f. 

 Water. 

 Spirits of wine. 



Ether. 

 Euphorbia juice. 



P. du Bois-Heymond^. 

 Warm oil. 

 Cold oil. 



Oil. 



Alcohol. 



Oil. 



Ether. 



Link\. 

 Water. 

 Fat oil. 



Petroleum. 



Oil of turpentine. 



Spirits of wine. 



Glycerine. 

 Alcohol. 



Glycerine. 

 Ether. 



31. The simplest case of the spreading of a liquid 2 on the 

 free surface of a liquid 1 is when the two liquids are miscible 

 in every proportion, and consequently in equation (4j a 12 must 

 be put =0. Then the liquid 2 with smaller capillary constant 

 spreads itself out on the liquid with the greater capillary con- 

 stant ; or, more accurately expressed, the greater tension of the 

 surface of liquid 1 draws to itself, as it were, the particles of 

 the surface of liquid 2 of lower tension of surface. 



P. du Bois-Reymond|| observed that a hot drop of a liquid, 

 placed on the surface of the same liquid not warmed, likewise 

 spread itself out there. As the capillary constant of a liquid 

 diminishes with increase of temperature, a l >oc 2 , and the expe- 

 riment can be predicted by the theory. 



The same observer^" has called attention to the currents pro- 

 duced in the interior of liquid 1 by the spreading of liquid 2 

 when he placed a layer of oil upon a layer of water instead of 

 upon a solid base. On the spreading of absolute alcohol on the 

 surface of the layer of oil, vortical movements take place in the 

 interior, and the water rises under the centre of the outspreading. 



These secondary phenomena may be explained, as P. du Bois- 

 Reymond** has already observed, in that the alcohol carries away 

 the layer of oil bordering on it, and appears every time more or 

 less strongly impressed as soon as a liquid 3 is placed on the thin 

 layer of liquid 2, which had spread itself out on the surface of 

 a liquid 1. The liquid 3 spreads on liquid 2 as soon as 



* Ann. de Chim. (1) vol. xlvii. p. 303 (1803). Gilb. Ann. vol. xxiv. 

 p. 131 (1806). 



t Ann. de Chim. (1) vol. li. p. 216 (1804). Gilb. Ann. vol. xxiv. p. 139 

 (1806). 



J Gilb. Ann. vol. xxiv. p. 123 (1806). 



§ Pogg. Ann. vol. civ. p. 196 (1858). || Ibid. p. 202 (1859). 



f Ibid. p. 197 (1859). ** Ibid. p. 199 (1859). 



Phil: Mag. S. 4. Vol. 41. No. 275. June 1871. 2 I 



