476 . REPORT — 1 894. 



When more water diffuses through the oil-film to the soap inside there 

 is formed a viscous liquid, a solution of the oleate in a jacket of oleic acid. 

 The movement of the water and the periodical spreading of soap-solution 

 will form long filaments or cylinders of viscous matter covered with an 

 oil-film. The oil-film contracts and forms bubbles in the middle and the 

 ends of the oil-filament. By the spreading of soap solution the bubbles 

 wander along the oil cylinders with different velocities and in different 

 directions. After some time the oil cylinders are deformed and become 

 strings of beads of oleic acid and thin oil- films. The thin oil-films form 

 foam or bubbles filled with water or weak solution of soap. 



In the oil-film are distributed lenses or spheres of oil filled with strong 

 or weak soap-solution. Some methylene-blue dissolved in the water is 

 collected or stored up in the oleic acid, so that the coloured oil and the 

 water may be very easily distinguished. 



The spheres of oleic acid coloured with methylene-blue are arranged on 

 the edges of the films of the bubbles or spherical films of the foam, and the 

 appearance is similar to the appearance presented by the stars of the 

 Milky Way. The formation of chains of stars, as observed by Professor 

 Max Wolf, and the spiral nebula in Perseus in the excellent photographs 

 of Dr. Roberts, are similar in appearance to the phenomena observed by 

 me in these microscopical oil-films and bubbles. 



Fifty years ago Plateau pointed to the analogy of the rotation of the 

 sun and the planets with the rotation of oil-spheres suspended in a mixture 

 of alcohol and water of the same density. Now we have a new analogy 

 between the arrangement of matter of the universe by forces acting at 

 very great or very small distances. From the standpoint of our modern 

 physics, with the Newtonian law of gravitation and the law of action of 

 molecular forces, these analogies may appear to be somewhat arbitrary. But 

 we must be able to pass from definite distances to infinitely great or to infi- 

 nitely small distances of the acting masses, and we can conceive that it 

 may be possible that the difference between the law of gravitation and the 

 law of the molecular forces may disappear, and that we may have the 

 same law for small and great distances ; so that the distribution of matter 

 may be accounted for by the same forces, when the masses and the 

 distances of the masses are increased in the same proportion, a million or 

 a billion times. 



The work of future generations will decide whether researches on the 

 microscopical oil-foam or on the stars of the universe will give the solution 

 of this problem. 



Oil the Displacements of the Eotational Axis of the Earth. Bij Professor 

 W. FoRSTER, Director of the Royal Ohser calory of Berlin. 



[Ordered by the General Committee to be printed in cxtcnso.'] 



Displacements of the rotational axis of the earth with reference to fixed 

 directions in space have been observed since the earliest ages of astro- 

 nomical measurement ; for such displacements, visible in wanderings of 

 the pole of the apparent diurnal rotation of the celestial sphere among the 

 constellations of fixed stars, exist in such enormous amplitudes, that in 

 their main features they could be detected by the aid of very simple 

 apparatus and observations. 



