THE FIGURES OF EQUILIBRIUM OF A LIQUID MASS 263 



§ 11. The existence of partitions is a fact well known to all who have 

 amnsed themselves with making soap bubbles ; but it was necessary to submit 

 to the control of experiment the results established in what precedes, from § 7 

 onward, and first those which relate to the curvature of the partition and the 

 angles under which that partition and the two films intersect each other. 



With that view I traced on three sheets of paper three figures, representing 

 the bases of three systems, each formed of two portions of laminar spheres and 

 of a partition. I understand by the base of such a system the assemblage of 

 arcs of a circle by which it rests on the surface of the liquid, abstraction being 

 made of the small annular masses. The three outlines are reproduced, at a 

 third of their size, by figures 12, 13, and 14 ; they were constructed upon the same 



Fiff. 12 Fi- 13 



Fi- U 



method with figure 11, the arcs being marked in lines about a niillirnetre in 

 breadth, for what reason will presently be seen. In the first drawing the 

 diameters of the two films were equal, in the second they were as 2 to 1, and 

 in the third as 3 to 1. To make use of one of these outlines, it was placed on 

 a table, and above it was laid a plate of thin glass, the upper iace of which was^ 

 then moistened with glyceric liquid. This being done, a bubble of the same" 

 liquid was inflated and was deposited on the glass plate above the porti-.m of 

 circumference which represented the base of the smallest film; this bubble im- 

 mediately spread so as to form a hemisphere, the base of which had, design- 

 edly, a diameter a little less than the portion of circumference in question. A 

 second bubble was then inflated, and in like manner deposited above the portion 

 of circumference representing the base of the other film, the precaution being 

 again taken that after its development on the glass it should have a diameter 

 somewhat smaller than that circumference. As, in depositing this second film, 

 it was placed in contact with the first, the two hemispheres penetrated one 

 another partially, and remained united with a partition. Matters being thus 

 prepared, the orifice of the pipe was dipped in glyceric liquid, as if to form a 

 bubble, and this orifice beiug then applied toward the inferior part of the 

 sulaller film, a little blowing was practiced ; the same operation was next per- 

 formed for the other film, then again for the first, then for the second, and so on, 

 the glass plate being at the same time made to slide, by small quantities, on the 

 drawing, and, with suitable care, it was contrived to give to the two films the 

 diameters of the portions of circumference as traced, and now the base of the 

 laminar system obtained, a base formed of those of the two films and that of 

 the partition, exactly covered the drawing. It has been said that the drawings 

 were in broad lines, and this was done because these lines were to be observed 

 through the small annular masses ; had the lines been fine, the refractions pro- 

 duced by these masses would have prevented them from being distinguished. 



§ 12. In order to verify also the results of § 9, I deposited successively on 

 the surface of the glyceric liquid, contained in the large porcL'laiu plate, (§ 3,) 

 two bubbles of this same liquid, in such manner that the two spherical caps 

 which they formed might be separated by a certain interval. When this was 

 about a centimetre, the films moved indeed toward one another, and united 

 with a partition; but if the two films had large diameters, (10 centimetres or 

 more,) the partition was not in general produced unless the union took place 



