To make this still more clear I will present it in a little different form. Let B, Fig. 84, be a close vessel with two tubes, one of which is five times as large as the other. If sufficient water be poured into the vessel to occupy a part of the tubes, it will stand at the same height in both tubes, as indicated. If there be a pound of water, then, in the tube _c_, there will be five pounds in _a_. Now if the five pounds of water in _a_ made any more pressure on the whole body of water in B than the pound of water in _c_ does, it would press up the water in _c_ to a greater height. But this is impossible, as has been shown in § 118. Observe that the five pounds of pressure in _a_ is spread over five times the area or extent of surface that the pound's pressure in _c_ is. If the tube _c_ have an area of an inch square, the water in it will exert a pressure of a pound on every square inch in the vessel. The water in _a_ exerts a pressure of five pounds; but it must be remembered that it does not press with this force on every square inch, but on every space of five square inches, and that therefore its pressure on every inch is the same as that in the tube _c_. 131. =Hydrostatic Paradox.=--You see in the phenomena and explanations given above that a small quantity of a fluid can, under certain circumstances, exert an enormous pressure. This fact has been called the Hydrostatic Paradox. It does seem, at first view, incredible or paradoxical, when one asserts that a few ounces of water can be made to raise weights of hundreds or even thousands of pounds. But the explanations which I have given show you that there is no unexplainable mystery in the fact. The cause of it is the same as that which gives a level surface to liquids; viz., the force of gravitation acting upon a substance whose particles are freely movable among each other. [Illustration: Fig. 85.]