262 THE FIGURES OF EQUILIBRIUM OF A LIQUID MASS 



ter, and attached by its extremities to solid parts, which cylinder preserves its 

 form so lonp: as it rcmaius imprisoned between the strips of glass. Weights are 

 next jilaccd upon the parts of the two copper wires which project beyond the 

 extremities of the bands, so as to maintain these wires in hrm positions; lastly, 

 by means which we shall point out presently, the two strips of glass are raised 

 vertically. At the same instant, the liquid cylinder, being liberated from its 

 shackles, becomes transformed into a numerous series of isolated spheres, ar- 

 ranged in a straight line in the direction of the cylinder from which they origi- 

 nated.* Ordinarily the regularity of the system of spheres thus obtained is 

 not perfect ; the spheres present diflerences in their respective diameters and in 

 the distances which separate them; this undoubtedly arises from slight acci- 

 dental causes, dependent u])on the method of operation ; but the differences are 

 sometimes so small that the regularity may be considered as perfect. As 

 regards the number of spheres corresponding to a cylinder of determinate 

 length, it varies in different experiments ; but these variations, which are also 

 due to slight accidental causes, are comprised within very small limits. 



51. Let us now complete the description of the apparatus, and add some 

 details regarding the operations. As the plate of glass requires to be placed in 

 a perfectly horizontal position, it is supported for this purpose upon four feet 

 with screws. A small transverse strip of thin paper is glued to each of the 

 extremities of the lower surface of the strips of glass, in such a manner that the 

 strips of glass resting upon the plate through the medium of these small pieces, 

 of paper, their lower surface is not in contact with the surface of the plate. 

 Without this precaution, the strips of glass might contract a certain adhesion to 

 the plate, which would introduce t^n obstacle when the strips are raised vertically. 

 Moreover, the latter are furnished, on their upper surface and at a distance of 6 

 millimeters from each of their extremities, with a small screw placed vertically 

 in the glass with the point upwards, firmly fixed to it with mastic, and rising 8 

 millimeters above its surface. These four screws are for the purpose of receiving 

 the nuts which fix the strips to the system by means of Avhich they arc elevated. 

 This system is made of iron ; it consists, in the first place, of two rectangular 

 plates, 55 millimeters in length, 12 in breadth, and 3 in thickness. Each of 

 them is pierced, perpendicularly to its large surfaces, by two holes, so situated, 

 that on placing each of these plates transversely upon the extremities of the two 

 strips of glass, the screws with which the latter are furnished fit into these four 

 holes. The screws being long enough to project above the holes, nuts may 

 then be adapted to them, so that on screwing them the strips of glass become 

 fixed in an invariable; position with regard to each otliQr. The holes are of an 

 elongated form in the direction of the length of the iron plates ; hence, after 

 having loosened the nuts, the distance between the two strips of glass may be 

 increased or diminished without the necessity of removing the plates. A vertical 

 axis, 5 centimeters in height, is implanted upon the middle of the upper surface 

 of each of the plates ; and the upper extremities of these two axes are connected 

 by a horizontal axis, at the middle of which a third vertical axis commences ; 

 this is directed upwards, and is 15 centimeters in length. The section of the 

 latter axis is square, and it is 5 millimeters in thickness. When the nuts are 

 screwed up, it is evident that the strips of glass, the iron plates, and the kind 

 of fork which connects them, constitute an invariable system. The long vertical 

 axis serves to direct the movement of this system ; with this view, it passes 

 with very slight fiiction through an aperture of the same section as itself, and 

 5 centimt.'ters in length, i)ierccd in a piece which is fixed very firmly by a suitable 

 support 10 centimeters above the plate of glass. Lastly, the perforated piece 

 is provided laterally Avith a thumb-screw, which allows the axis to he screwed 



* Wc may remark that tlic conversion of a iiietallic wire into globules by the cloctiic dis- 

 charge must undoubtedly be referred to the same order of phenomena. 



