WITHDRAWN FROM THE ACTION OF GRAVITY. 261 



state nf repose was unstable. lu explaining this apparent peculiarity, we must 

 remark that, as the spontaneous transformation of an unstable cylinder is effected 

 under the action of continued forces, the rapidity with which the phenomenon 

 occurs ought to be accelerated ; this may be, moreover, easily verified in experi- 

 ments relating to larger and less elongated cylinders ; this same rapidity ought, 

 therefore, always to be very minute at the commencement of the phenomenon. 

 Now, in the case in question, as the changes in figure occur in the liquid of the 

 cylinder whilst this liquid is animated by a movement of transference, it is 

 evident, from A\'hat we have stated, that if this movement of transference is 

 sufficiently rapid, the changes of form could only acquire a very slightly marked 

 development during the passage of the point of the funnel to th(! mass accumu- 

 lated at the bottom of the vessel ; so that, the liquid being continually renewed, 

 there will be no time for any alte>ration in form to become very perceptible to 

 the eye. Hence, so long as the rapidity of the flow is sufficiently gn-at, the 

 liquid figure will appear to retain its almost cylindrical form, although its length 

 is considerable in comparison with its diameter. On the other hand, when the 

 velocity of the transference is sufficiently small, there will be time for the 

 alterations in form to take place in a perfect manner, and we shall be able to 

 see the cylinder resolve itself into spheres throughout the whole of its length. 



50. We shall now describe another method of experimenting, which allows 

 us to observe the result of the transformation under less restrained and more 

 ^regular conditions in some respects than those of the preceding experiment, and 

 which will, moreover, lead us to new consequences as regards the laws of the 

 phenomenon. We shall first succinctly describe the apparatus and the opera- 

 tions, and afterwards add the necessary details. 



The principal parts of which the apparatus consists are : 1st, a rectangular 

 plate of plate-glass, 25 centimeters in length, and 20 in breadth; 2d, two strips 

 of the same glass, 13 centimeters in length, and fr millimeters in thickness, 

 perfectly prepared and polished at the edges ; 3d, two ends of copper wire, 

 about 1 millimeter in thickness, and 5 centimeters in length; these wires should 

 be perfectly straight, and one extremity of each of them should be cut very 

 accurately, then carefully amalgamated. The plate being placed horizontally, 

 the two strips are laid tiat upon its surface and parallel with its long sides, so 

 as to leave an interval of about a centimeter between them ; the two copper 

 wires are then introduced into this, placing them in a right line in the direction 

 of the length of the strips, and in such a manner that the amalgamated extremi- 

 ties are opposite to, and a few centimeters distant from, each other. A globule 

 of very pure mercury, from 5 to 6 centimeters in diameter, is next placed be- 

 tween the same extremities ; the two strips of glass are then approximated 

 until they touch the wires, so as only to leave between them an interval equal 

 in width to the diameter of these wires. The little mass of mercury, being 

 thus compressed laterally, necessarily becomes elongated, and extends on both 

 sides towards the amalgamated surfaces. If it does not reach them, the wires 

 are made to slide towards them until contact and adhesion are established. 

 The wires are then moved in opposite directions, so as to separate them from 

 each other, which again produces elongation of the little liquid mass and dimi- 

 nution of its vertical dimensions. By proceeding carefully, and accompanying 

 the operation with slight blows given with the finger upon the apparatus to 

 facilitate the movements of the mercury, we succeed in extending the little 

 mass until its vertical thickness is every where equal to its horizontal thickness, 

 *'. e., to that of the copper wires. Thus the mercury forms a liquid wire of the 

 same diameter as the solid wires to which it is attached, and from 8 to 10 cen- 

 timeters in length. This wire, considering the small size of its diameter, which 

 renders the action of gravitation insensible in comparison with that of molecular 

 attraction, may be considered as exactly cylindrical; so that in this manner we 

 obtain a liquid cylinder, the length of which is from 80 to 100 times its diame- 



