WITHDRAWN FROM THE ACTION OF GEAVITY. 209 



assume a splicrical form more or less perfect. Leaving these minute quantities, 

 if we wish to observe liquid masses which have freely taken a certain form, we 

 must quit the earth, or rather consider the terrestrial globe itself and the other 

 planets as having been primitively fluid, and having ackpted their exterior form 

 to the combined action of gravitation and centrifugal force. Theory then indi- 

 cates that these masses ought to take the form of spheroids more or less flattened 

 in the direction of their axis of rotation, and observation confirms these deduc- 

 tions of theory. Observation shows us, also, around Saturn, a body of annular 

 form, and theory finds, in the combined actions of gravity and centrifugal force, 

 means of satisfying the equilibrium of that singular form. 



If, however, Ave could, by some means, withdraw from the action of gravity 

 orfe of the liquid masses upon which we have to operate, at the same time 

 leaving it free to be acted upon by other forces which -might tend to modify its 

 form, and if our process allowed of giving to this mass sufficiently large dimen- 

 sions, would it not be very curious to see it take a determinate figure, and to 

 see this figure vary in a thousand ways with the forces on which it depends? 

 Now I have succeeded, by an extremely simple means, in submitting to the 

 above conditions a considerable liquid mass. 



2. Fat oils are, it is known, less dense than water, and more dense than alco- 

 hol. Accordingly, w^e may make a mixture of water and alcohol having a den- 

 sity precisely equal to that of a given oil — of olive oil, for example. Now, if 

 any quantity of olive oil is introduced into the mixture thus formed, it is evident 

 that the action of gravity upon this mass of oil will be completely annihilated ; for, 

 in virtue of the equality of density, the oil will only hold the place of an equal 

 mass of the ambient liquid. On the other hand, the fat oils do not mix with a 

 liquor composed of alcohol and water. The mass of oil must therefore remain sus- 

 pended and isolated in the midst of the surrounding liquid, and it will be per- 

 fectly free to take the exterior form which the forces that may act upon it will 

 give to it. 



This being supposed, if the molecular attractions of the oil for itself, those of 

 the alcoholic mixture for itself, and those of this mixture for the oil were identi- 

 cal, there would be no reason that the mass of oil left in the midst of the ambient 

 liquid should take spontaneously oue form more than another, since, relatively, 

 to all the forces acting upon it, it Avould be exactly in the same position as an 

 equal mass of alcoholic mixture whose place it would occupy. But it is evident 

 that this identity between the difierent attractive forces does not exist, and that 

 the attraction of the oil for itself greatly exceeds the two others. The mass of 

 oil, therefore, ought to obey this excess of its own attractive forces. 



We thus come to this conclusion, that our mass of oil may be perfectly as- 

 similated to a liquid mass without weight, suspended freely in space, and sub- 

 mitted to its own proper molecular attractions. Now, it is clear that such a 

 mass must take the spherical form. 



Well, exj^eriment confirms all this in a complete manner. The mass of oil, 

 ■whatever its volume, remains, in fact, suspended in the midst of the alcoholic 

 liquid, and takes the form of a perfect sphere. 



3. In order to obtain this singular result with facility, it is necessary to take 

 certain precautions, wdiich I Avill describe. 



The first concern the formation of the alcoholic mixture. The density of this 

 mixture necessarily varies with the kind of oil Avhich is itsed. For the olive oil 

 which I employed, and for the purity of which I cannot vouch, the proper mixture 

 marked twenty-two degrees on the areometer of Beaumo. If, therefore, auy one 

 wishes to use olive oil, he may always consider the above vlilue as n first approx- 

 imation, and, by successive attempts, will bring the liquor at length to the exact 

 point which it ought to reach. To accomplish this, a test tube is filji'd with 

 the liquor, into which a little oil is afterwards poured by means of a long-necked> 

 funnel, which reaches about half way down the test tube. The oil, on reaching 

 14 s 



