the Adhesion of Liquids to Liquids. 409 



tween the teeth or rays run deeper in than others. Each tootli 

 or ray as it contracts leaves dots of oil regularly placed behind 

 it. In this state it forms tig. 5, the formation of the dots being 

 shown in fig. 5 a. Then the deep indentations run more deeply 

 and rapidly in, to branch out into rounded hollows within the 

 disk, as in fig. 6. These ramifications increase and deepen, until 

 they break up the central disk into a number of small disks, 

 which finally remain arranged somewhat symmetrically, as in 

 fig. 7. If the creosote be put first upon the surface, the corian- 

 der instantly arrests its motions. In a recent experiment the 

 creosote split up into a number of active figures, which the co- 

 riander rendered motionless. But in the course of twenty mi- 

 nutes the smallest of the creosote disks became active, cleared a 

 small space in the film for its operations, soon became wildly 

 active, and disappeared with frantic gesticulations. Then the 

 large disks became active. It seemed as if the coriander film 

 had at first closed in all round the creosote figures and stopped 

 them; but as the creosote retained possession of the spots of 

 water on which they actually stood, they waited their time, and 

 as the coriander film became weakened by evaporation and solu- 

 tion the creosote gradually repelled it and soon made a clear 

 space for its own exertions. Having once secured this space, it 

 extended it, and passed over the whole surface, carrying its own 

 clear surrounding space along with it. Indeed the manner in 

 which the creosote figure cuts through some films without touch- 

 ing them is a remarkable sight. As the figure advances, the film 

 recedes, sometimes one, or two, or three tenths of an inch, or more 

 from the figure. It is at the edge of the figure that the chief 

 contest between cohesion and adhesion is going on, and here it 

 is that solution takes place and the figure wastes away : it is 

 always surrounded by a solution which wells away outwards, and 

 which, though invisible, makes its presence felt by its repulsive 

 action. The outward action is also evident by the globules of 

 creosote which are discharged in radial lines from the figure. 



Oil of lavender, unless recently distilled, permanently arrests 

 the motions of the creosote figure ; and even the fresh oil does 

 so for a very long time. A drop of the oil on water makes its 

 beautiful cohesion- figure*, which terminates in a multitude of 

 small lenses connected by a film which easily resinifies by expo- 

 sure to the air. But even in such a case the creosote in the 

 course of an hour or so became active, and repelled the film, its 

 duration being estimated by hours instead of minutes. 



If further proof were wanting of the remarkable force of ad- 

 hesion that exists between creosote and the surface of water, it is 

 to be found in the fact that creosote displaces many of the fatty 

 * See Phil. Mag. October 1861, Plate IV,] 



