WITHDRAWN FROM THE ACTION OF GRAVITY. 631 



distance was measured by a scale introduced into the vessel 

 and kept in a vertical position by the side of the liquid figure. 

 In consequence of the excess of oil, the meridional line of the 

 figure was convex externally ; and as there was still a slight 

 difference between the densities, this convexity was not symme- 

 trical in regard to the two rings. I corrected this irregularity 

 by successive additions of pure alcohol and alcohol of 16°, an 

 operation which requires great circumspection, and towards the 

 end of which these liquids could only be added in single drops. 

 The figure being at last perfectly symmetrical, I carefully re- 

 moved the excess of oil by applying the point of the syringe to 

 a point at the equator of the mass, and in this manner I obtained 

 a perfect cylinder. Subsequently, after having added some oil 

 to the mass, I increased the distance between the rings until it 

 was equal to 8 centims., i. e. to four times their diameter. The 

 oil was in sufficient quantity to allow of the meridional line of 

 the figure being convex externally ; but the curvature was not 

 perfectly symmetrical, and I encountered still greater difficulties 

 in regulating it than in the preceding case. The defect in the sym- 

 metry being ultimately corrected, the meridional convexity pre- 

 sented a versed sine of about 3 miUims. (fig. 25). I then proceeded 

 to the removal of the excess of oil ; but before the versed sine was 

 reduced to 2 millims., the figure appeared to have a tendency to 

 become thin at its lower part and to swell out at the upper part, 

 as if the oil had suddenly become slightly increased in density. 

 At this moment I withdrew the syringe, so as to be enabled to 

 observe the effect in question better ; the change in form then 

 became more and more pronounced ; the lower part of the figure 

 soon presented a true strangulation, the neck of which was 

 situated nearly at a fourth part of the distance between the rings 

 (fig. 26) ; the constricted portion continued to narrow gra- 

 dually, whilst the upper part of the figure became swollen; 

 finally, the liquid separated into two unequal masses, which re- 

 mained respectively adherent to the two rings ; the upper mass 

 formed a complete sphere, and the lower mass a doubly convex 

 lens. The whole of these phaenomena lasted a very short time 

 only. 



With a view to determine whether any particular cause had 

 in reality produced the alteration of the densities, I approximated 

 the rings ; then, after having reunited the two hquid masses, I 

 again carefully raised the upper ring, ceasing at the height of 



