406 Mr. C. Tomlinson on some Phenomena connected with 



A drop of benzole on the surface flattened out into a disk 

 about an inch in diameter. The moment the creosote touched 

 the water, the benzole reasserted nearly the whole of its cohe- 

 sive force, and shrunk up into a double-convex lens. The creosote 

 figure played about this lens and drove it about ; and the dura- 

 tion of the figure was, as in the other cases, greatly increased. 



A drop of Persian naphtha spread out into a film. The creo- 

 sote figure did not make it collapse as in the case of benzole, 

 but ploughed through it and cut it up in various directions, as 

 camphor does through films of newly distilled essential oils*. 



Small portions of certain soluble salts greatly diminish, or 

 even destroy the adhesion of the surface of the water. About 

 three-quarters of an ounce of a hot saturated solution of sulphate 

 of magnesia was poured into the glass, which was filled up with 

 about 1^ ounce of cold distilled water. A drop of creosote 

 gently delivered to the surface sank to the bottom, and remained 

 apparently without change during twenty-four hours. 



Twenty grains of sulphate of magnesia were put into the glass 

 and 2 ounces of cold distilled water poured in. When the salt 

 was dissolved, a drop of creosote was placed on the surface. It 

 formed a large flat circular disk, the edge of which showed 

 minute vibrations. After a few minutes a portion only of the 

 edge vibrated, the other part being rounded and sharp. In 

 this way it made several attempts at vibration and progressive 

 motion ; but after about twenty minutes it became inactive, and 

 continued so during twenty-three hours, gradually diminishing 

 in size during that time. 



It thus appeared that a much less quantity than 20 grains 

 would suffice to lower or destroy the adhesive force of the sur- 

 face. Five grains of Epsom salts to the 2 ounces of water ex- 

 tended the duration of the figure from five to fifteen minutes. Six 

 drops of the saturated solution (cold) added to the water, extended 

 the duration to fourteen minutes and a half, and prevented the 

 quivering of the surface. A second drop of creosote placed on 

 the surface when the first had disappeared, sank to the bottom. 



Four grains of common salt extended the duration to fifteen 

 minutes; 4 grains of alum rendered the figure inactive in four- 

 teen minutes ; 6 grains of acetate of soda in 2 ounces of water 

 at 70° did not seem to disturb the activity of the figure, but 

 changed its character to a shuffling kind of motion. The figure 

 was greatly influenced by the capillarity of the side, sailing- 

 round near the edge, and leaving behind it, rather than throw- 

 ing out, numerous small disks, which, usually so active, were in 

 this case inactive. The duration of the figure was thirteen 

 minutes. 



* See Phil. Mag. for September 1863. 





