WITHDRAWN FROM THE ACTION OF GRAVITY. 221 



tres was gubstitutcd *, whicli renders necessarj^, in order to form tlie ring well, 

 a less velocitj of rotation than with the preceding disc, (the most suitable ap- 

 pears to me to be a little less than two turns in a second.) Noav, instead of 

 stopping the movement of the disc at the instant Avhen the ring has attained its 

 greatest development, we must continue to move the handle. The film of oil 

 will then break in a little time, as if the disc had been stopped ; but, the latter 

 continuing to revolve in the alcoholic liquor, the portions of that liquor whicli 

 are in contact with it will themselves assume a rotatory movement, and the 

 cenirifugal force which results from it will drive them continually towards the 

 ring, so that the latter'will not be able to i-eturn upon itself. Now, in these 

 circumstances, we soon see the ring lose its regularity, then divide into several 

 isolated masses, each of which immediately takes the spherical form. Thus the 

 ring, when it cannot preserve its ligure on account of the decrease of its cen- 

 trifugal force, and an obstacle prevents its reforming itself into a single sphei'e, 

 resolved itself into several isolated spheres. As soon as the separation begins 

 to take place, the movement of the disc must be stopped. 



This is not all : one or more of these spheres are then almost ahvays seen 

 to assume, at the instant of their formation, a movement of rotation ujiou them- 

 selves — a movement which constantly takes place in the same direction as that 

 of the ring. Moreover, as the ring, at the instant of its rupture, had still a re- 

 mainder of velocity, the spheres to which it has given birth, tend to* fly off at a 

 tangent ; but as, on the^other side, the disc, turning in the alcoholic liquor, has 

 impressed on this a movement of rotation, the spheres are especially carried 

 along by this last movement, and revolve for some time around the disc. Those 

 which revolve at the same time upon themselves consequently then present the 

 curious spectacle of planets revolving at the same time on themselves and in 

 their orbit. The movement of rotation of these masses is, however, too slow, in 

 relation to their diameter, to cause any sensible flattening. Finally, another 

 very curious effect is also manifested in these circumstances. Besides three or 

 four largo spheres into which the ring resolves itself, there are almost always 

 produced one or two very small ones, which may thus be compared to satellites. 



The experiment which we have just described, presents, as we see, an image 

 in miniature of the formation of the planets, according to the hypothesis of 

 Laplace, by the rupture of the cosmical rings attributable to the condensation 

 of the solar atmosphere. 



20. When some oil is introduced into a mixture containing a little excess of 

 alcohol, a phenomenon is observable, which is connected with that of the ixiso- 

 lution of the ring into isolated spheres. If the oil be poured in with sufficient 

 rapidity it forms a long cylindrical train, extending from the beak of the funnel 

 to the bottom of the vessel, where the mass gathers. .Now, this kind of tail, 

 which connects the mass of oil with the beak of the funnel, remains as long as 

 the oil which forms it has a sufficiently rapid movement of translation — that is 

 to say, as long as we continue to pour ; but, as soon as we cease to pour out, 

 and the movement of translation is slackened, the train of oil is instantly re- 

 solved into several isolated spherules. 



21. The formation of a ring analogous to that of Saturn naturally inspires 

 the desire to carry further the resemblance to the system of that planet, and to 

 seek, whether, by some modification of our experiment, it Avould not be possible 

 to contrive so that a sphere of oil should remain in the middle of the ring. Now, 

 I have succeeded in producing this effect, by means of a process which I shall 

 proceed to describe ; only that this experiment rjiust be regarded merely as a scien- 

 tific sport, for the circumstances which give rise to the result have evidently no anal- 

 ogy with those which can have occasioned the configuration of the system of Saturn. 



* This substitution is accomplished by tletaching the upper end of the axis of the first disc 

 from the large wire which passes through the metallic stopper ($8,) and screwing }n its 

 place the end of the axis of the new disc. 



