Liquid Drops on the Same Liquid Surface

Article metrics


DR. M. KATALINIĆ has described a method of producing floating drops of clean water on a water surface by delivery from a suitably situated jet.1 Such drops must owe their existence to the stability of the film immediately beneath them, that is, the thickness-coefficient of the surface tension of the film over a suitable range must be negative, a characteristic of all stable films such as those of soap. Therefore a drop of soap solution should be stable on a water surface, the hydrophobic ends of the soap ions in the surface being directed outwards, and we were able last August to produce such drops of any diameter up to about 1 cm. by simply dipping a piece of soap (any kind) in water and allowing the drops to fall off it on to the surface from a height of about 1 cm. It is best to draw the soap down in a sweeping curve into the water and then out. In this way the floating drops are propelled forward and travel for distances up to quite 1 metre, if they are not too large. The very large drops last for scarcely one second, but the smaller ones for much longer. We experimented in a large tank of rain water illuminated by the sun, and interference colours were easily observed in the film beneath the drops. Later we obtained the same results in a beaker of distilled water, or even in tap water. The observations we made were, in the main, the same as those recorded by Dr. Katalinić.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    NATURE, 127, 627, April 25, 1931.

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

HUGHES, W., HUGHES, A. Liquid Drops on the Same Liquid Surface. Nature 129, 59 (1932) doi:10.1038/129059a0

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.