410 Mr. C. Tomlinson on some Phenomena connected with 



oils. For example, a drop of castor-oil nearly covered the sur- 

 face with its beautiful cohesion-figure. In this case a larger 

 glass was used, 4 inches in diameter instead of 3. A drop of 

 creosote placed at the side instantly became active, causing the 

 oil to contract into a lens and chasing it about. When the creo- 

 sote had disappeared, the oil flattened out into a film that occu- 

 pied nearly the whole surface. A second drop of creosote did 

 not shut it up agaiu, but ploughed through it, turning over and 

 thickening the edges of the severed portions. The film was now 

 in long trails, which were swept about by the vibrating figure. 

 When this had disappeared, these trails flattened out and again 

 nearly covered the surface. A third drop of creosote cleared a 

 wide space among the films, like open water in ice. A film of 

 castor-oil on warm water is spun out into threads by the action 

 of the creosote; that is, the film, instead of being cut through, 

 is united by a thread which spins off from one part of the nearly 

 severed portion to the other, until the part which gives the 

 thread is exhausted. 



The creosote figure also repelled and cut up films of whale-oil, 

 fish-oil, nut-oil, and several other fatty oils. A pale seal-oil, 

 very pure and limpid, made a large film. The creosote figure 

 repelled it strongly, but did not shut it up. As the figure moved 

 about it made deep bays in the edge, which yielded as the figure 

 travelled along. The effect was as if a ship were invading the 

 land and carrying its own water, for many feet round it, to sail 

 in. The film formed by balsam of copaiba is at once invaded by 

 the creosote figure, which continues active during twenty minutes 

 or more. 



In the preceding details creosote has been taken as the stand- 

 ard, and the adhesive force of the water judged of with reference 

 to it. Oils of the turpentine series and some other essential oils 

 arrest the motions of the creosote figure only for a short time. 

 As the film of oil becomes thinner the creosote becomes active, 

 and completes its course. Now the time occupied by the figure 

 in doing this may be taken as a sort of measure of the adhesion 

 of the surface for the oil in question. If a film of turpentine 

 extend the duration of the creosote figure to ten minutes, and a 

 film of oil of nutmegs to twenty minutes, it is presumed that the 

 latter oil adheres twice as strongly to the surface as the former. 

 So, when the creosote displaces films, and its duration is scarcely 

 prolonged at all, the adhesion between the water and the film 

 can be but small. Where the duration of the creosote, without 

 losing its activity, is considerably extended, the adhesion of the 

 film must be considerable. It is thought that in this way 

 Tables of the adhesive force of different liquids for each other 

 may be framed. 



