WITHDRAWN FROM THE ACTION OF GRAVITY. 259 



would require still less trouble ; the distance in question is only 108 millime- 

 ters, so that the relation between the length and the diameter of the liquid 

 cylinder which would extend between the two disks would be equal to 3.6. 



We shall now detail the results obtained by the employment of this system. 

 In the first place, the operations were much more easily performed.* In the 

 second place, the figure still bad a tendency to deformity before it had been 

 rendered perfectly cylindrical ; but this tendency always exhibited itself uusym- 

 metrically, as in the vertical figures ; from which circumstance alone we m<ght 

 conclude that the unsymmetrical nature of the phenomenon is not occasioned by 

 a difference between the densities of the two liquids. In the third place, by a 

 little management, I have pursued the experiment further, and succeeded in 

 forming an exact cylinder.! This lasted for a moment; it then began to bo 

 narrowed at one part of its length, becoming dilated at the other, like the verti- 

 cal figures; and the phenomenon of disunion was completed in the same manner, 

 giving rise ultimately to two masses of difierent volumes. 



I repeated the experiment several times, and always with the same results, 

 except that the separation occurred sometimes on . one, sometimes on the other 

 side of the middle of the length of the figure. However, although the phe- 

 nomenon is produced in an unsymmetrical manner with regard to the middle of 

 the length of the figure, whether horizontal or vertical, on the contrary there is 

 always symmetry with regard to the axis; in other words, throughout the dura- 

 tion of the phenomenon the figure remains constantly a figure of revolution. 

 We may add here, that in the horizontal figure the respective lengths of the 

 constricted and dilated portions appear to be equal ; we shall show, in the fol- 

 lowing series, that this equality is rigorously exact, at least at the commencement 

 of the phenomenon. 



It is now evident that the alteration in the form of these cylinders is really 

 the result of a property which is inherent in them. We shall hereafter deduce 

 this property as a necessary consequence of the laws which govern a more 

 general phenomenon. 



It moreover results from the above experiment that the proportion 3.6 is still 

 greater than the limit of stability, so that the exact value of the latter must lie 

 between the numbers 3 and 3.6. It is obvious that this method of experiment 

 might be employed to obtain a closely approximative determination of the value 

 in question ; I propose doing this hereafter, and I shall give an account of the 

 result in the following series, when I shall have to return to the question of the 

 limit of stability of the cylinder. 



47. In the unstable cylinders which we have just formed, the proportion of 

 the length to the diameter was inconsiderable; but what -stould be the case if we 

 were to obtain cylinders of great length relatively to their diameter? Now, 

 under certain circumstances, figures of this kind, more or less exactly cylindri- 

 cal, may be realized, and we shall proceed to see what the results of the spon- 

 taneous rupture of equilibriury are. 



* The two disks in this solid system being placed at an invariable distance from each 

 other, it is necessary, in making a mass of oil, the volume of which is not too great, adhere 

 to them, to employ an extra piece consisting of a rlDg of iron wire of the same diameter as 

 the disks, supported by a straight wire of the same metal, the free extremity of which is held 

 in the hand. By means of this ring the mass, which has been previously attached to one of 

 the disks, is drawn out until it is equally attached to the other; tho ring is then reaioved. 

 The latter removes a small portion of the nfass at the same time ; but on leaving the vessel it 

 leaves this portion in the alcoholic liquid. It is then removed by means of the syringe. 



t To effect this the following proceeding must be adopted for the removal of the excess of 

 oil. The operation is at first carried on with a suitable rapidity until the figure begins to 

 alter in form ; the end of the point of the syringe is then drawn gently along the upper part 

 of the mass, proceeding from the thickest to the other portion. This slight action is sutBciont 

 to move a minute quantity ot oil towards the latter, and thus to re-establish the symmetry 

 of the figure ; a new absorption is then made, the figure again regulated, and these proceed- 

 ings are continued until the exactly cylindrical form is attained. 



