(99.) When a body is in the liquid form, the weight of its particles greatly predominates over their mutual cohesion, and consequently if such a body be unconfined it will be scattered by its own weight; if it be placed in any vessel, it will settle itself, by the force of its weight, into the lowest parts, so that no space in the vessel below the upper surface of the liquid will be unoccupied. The particles of a solid body placed in the vessel have exactly the same tendency, by reason of their weight; but this tendency is resisted and prevented from taking effect by their strong cohesion. Although this cohesion in solids is much greater than in liquids, and productive of more obvious effects, yet the principle is not altogether unobserved in liquids. Water converted into vapour by heat, is divided into inconceivably minute particles, which ascend in the atmosphere. When it is there deprived of a part of that heat which gave it the vaporous form, the particles, in virtue of their cohesive force, collect into round drops, in which form they descend to the earth. In the same manner, if a liquid be allowed to fall gradually from the lip of a vessel, it will not be dismissed in particles indefinitely small, as if its mass were incoherent, like sand or powder, but will fall in drops of considerable magnitude. In proportion as the cohesive force is greater, these drops affect a greater size. Thus, oil and viscid liquids fall in large drops; ether, alcohol, and others in small ones. Two drops of rain trickling down a window pane will coalesce when they approach each other; and the same phenomenon is still more remarkable, if a few drops of quicksilver be scattered on an horizontal plate of glass. It is the cohesive principle which gives rotundity to grains of shot: the liquid metal is allowed to fall like rain from a great elevation. In its descent the drops become truly globular, and before they reach the end of their fall they are hardened by cooling, so that they retain their shape. It is also, probably, to the cohesive attraction that we should assign the globular forms of all the great bodies of the universe; the sun, planets, satellites, &c., which originally may have been in the liquid state. (100.) Molecular attraction is also exhibited between the particles of liquids and solids. A drop of water will not descend freely when it is in contact with a perpendicular glass plane: it will adhere to the glass; its descent will be retarded; and if its weight be insufficient to overcome the adhesive force, it will remain suspended. If a plate of glass be placed upon the surface of water without being permitted to sink, it will require more force to raise it from the water than is sufficient merely to balance the weight of the glass. This shows the adhesion of the water and glass, and also the cohesive force with which the particles of the water resist separation.