Suppose this liquid to be A, then let us consider the forces which will act on the portion _a_, _b_, of this liquid. At the extremity _a_, it will be submitted to the attraction of the exterior fluid A: at the extremity _b_, it will be attracted in the opposite direction by the liquid B. Now the two liquids being different, their attractions will be unequal, and we will suppose that that of B, on the matter [p196] of A, is greater than that of A for itself. As to the action of the canal on the portion _a_, _b_, that will be equal, and exerted in contrary directions at its two extremities; it will not, therefore, be either adverse or favourable to the movement of the fluid in the canal: and the same will be the case with respect to the pressures exerted at _a_ and _b_, by the external liquids, as long as they are equal: nevertheless, the action of the canal, and the external pressures, will prevent the thread of fluid from being broken, so that it will move without interruption in the direction in which it is drawn by the greatest attraction, or from _a_ to _b_. Hence will result an elevation of the level of B, and, consequently, an increase of pressure at the extremity _b_, of the passage, and this elevation will proceed until the difference of pressure in _a_ and _b_ shall be equal to that of the attractions exerted by the two fluids A and B, on the thread _a b_; this effect will be produced the more rapidly as the division is pierced with a greater number of passages similar to that which has been considered.