WITHDRAWN FROM THE ACTION OF GRAVITY. 599 



abruptly at this rim without passing to the other side of the 

 plate, and thus presents a sudden interruption in the curvature 

 of its surface. In the case in question, the new figure acquired 

 by the mass is a portion of a sphere. This portion will be 

 as much larger in proportion to the complete sphere as the 

 volume of oil is greater ; but the curvature will always terminate 

 abruptly at the margin of the plate (see fig. 2, which represents 

 a section of the solid system and the adherent mass in the case 

 of three different volumes of the latter). 



The cause of this singular interruption of continuity is readily 

 understood. The rim of the plate reaching to the superficial 

 layer, it is natural that something peculiar should occur along 

 this margin, and that the continuity of form should cease at that 

 point where a foreign attractive action is exerted without trans- 

 ition on the superficial layer. 



14. Let us again make use of the above plate ; but instead of 

 presenting one of its faces to the exterior of the sphere of oil, 

 let us insert the plate edgewise into the interior of this sphere*. 

 The liquid will necessarily extend over both faces of the solid; 

 and if the diameter of the primitive sphere were less than that 

 of the plate, the oil will be seen to form two spherical segments 

 upon the two faces in question, the curvatures of which will still 

 terminate abruptly at the margin of the plate. These two seg- 

 ments may be either equal or unequal, according as the edge 

 of the pfate has been introduced into the liquid sphere in such 

 a manner that the plane of the plate passes through the centre 

 of the sphere or not. The upper segment will be slightly de- 

 formed by the action of the suspending wire ; but this effect will 



* This operation is performed as follows. The stopper to which the 

 system of the plate is attached is kept at some distance above the neck of the 

 central aperture, in such a manner however that the latter is immersed to a 

 sufficient depth in the alcoholic mixture. The plate can then be moved with 

 tolerable freedom, and it is conducted towards the liquid mass. For this pur- 

 pose, tiie latter ought previously to occupy a suitable position. Immediately 

 the liquid mass is cut, the plate is kept still until the action is terminated, after 

 which tlie stopper is carefully placed in the neck. A process the reverse 

 to the preceding may also be made use of. The liquid mass is first made 

 to occupy a position near the second aperture, and a sufficient distance from 

 the axis which passes through the centre of the central aperture ; then, having 

 fixed the solid system firmly in the position which it is to occupy, move the 

 liquid mass towards it, and when this has been cut, allow the action to continue 

 uninterruptedly. 'J'hose processes are also employed in other experiments, 

 and it is enough to have pointed them out once. In some cases the second is 

 the only practicable one. This may be easily decided upon in making the 

 experiments. 



