248 THE FIGUKES OF EQUILIBRIUM OF A LIQUID MASS 



their continuity, that the summits of these pyramids should not constitute sim- 

 ple points, but little concave surfaces. Bat as the curvatures of these minute 

 surfaces are very great in every direction, they would give rise to still far less 

 pressure than those which establi.sh the transitions between each pair of sur- 

 faces of the layers ; for in the latter there is no curvature in one direction. 

 The oil of the la^'ers will, therefore, be driven with ranch greater force towards 

 the centre of the figure than towards the other parts of^ the junctions of these 

 layers. Again, the twelve layers terminating in this same centre, the oil flows 

 there siniultaneou:?ly from a large number of sources. 1'hese two concurrent causes 

 ought then, in conformity with experiment, to produce the rapid reappearance of 

 the small central mass ; and we can understand why it is impossible to obtain the 

 complete sys^tem of the ])yramids otherwise than during the action of the syringe. 

 34. All the other polyhedric liquids become transformed, like the cube, into 

 laminar systems Avhen the mass of which they are composed is gradually 

 diminished. Among these systems some are complete ; the others still contain 

 very small masses, which cannot be made'to disappear entirely. Analogous 

 considerations to those which we applied with regard to the cube would shdw, 

 in each case, that the formation of layers commences as soon as the hollow 

 surfaces which would correspond to the ordinary law of pressures cease to be 

 able to coexist in the solid frame. Figs. 15, IG, 17, and 18 represent the 



Jt.jY3. 



Fn/./6 



laminar systems resulting from the triangular prism, the hexahedral prism, the 

 tetrahedron and the pyramid with a square base, these systems being supposed 

 to be complete. They arc all formed of ])laue layers, commencing at each of 

 the metallic wires; and that of the hexahedral prism, as is "shown, contains a,n 

 additional layer iu the centre of the figure. 



Fiff. 19. 



JFig. 20. 



3v.. Tlie system aiismg from the regular octohedron presents a singular 

 exception, which I have not been able to explain. The layers of which this 

 system is composed arc curved, and form a fantastical group, of which it is 

 difficult to give an exact idea by graphic representations. Eig. 19 cxhibit,s 



