. The principles of physics. s stated. For a like reasonthe downward pressure in a body of liquid increases as itsdepth except in so far as the pressure is modified in conse-quence of the compressibility of liquids. Liquids are, how-ever, so slightly compressible that any variation in conse-quence of the compression is usually neglected, and theprinciple is stated in general that pressure at any point in aliquid varies as its depth. Since the shot possess a certain degree of mobility or free-dom of motion around one another, their weight will cause tosome extent a lateral pressure against one
. The principles of physics. s stated. For a like reasonthe downward pressure in a body of liquid increases as itsdepth except in so far as the pressure is modified in conse-quence of the compressibility of liquids. Liquids are, how-ever, so slightly compressible that any variation in conse-quence of the compression is usually neglected, and theprinciple is stated in general that pressure at any point in aliquid varies as its depth. Since the shot possess a certain degree of mobility or free-dom of motion around one another, their weight will cause tosome extent a lateral pressure against one another and againstthe walls of the con- --^— taining vessel. In consequence of the extreme mobility of .^^c^::g^6^^^=9=^=y^=-^rg^=^s=^ the molecules of fluids p the downward pres- g sure due to gravita- - ^^^=^ tion at any point in ^^- ^o^- a fluid gives rise to an equal pressure at that point in all directions. Hence the so-called Pascals principle: At any point in a fluid at rest the pressure is equal in all 148 MOLAR DYNAMICS. Thus, let a, b, c, etc. (Fig. 109), represent imaginary surfaces,and the arrow-heads the direction of pressure exerted atpoints in these surfaces at equal depths in a liquid. Thepressures exerted at these several points are equal. The truth of this principle is obvious, for if there be anyinequality of pressure at any point, the unbalanced force willcause particles at that point to move, which is contrary to thesupposition that the fluid is at rest. Conversely, when thereis motion in a body of fluid it is evidence of an inequalityof pressure. 126. Methods of calculating liquid pressure. — Conceive ofa square prism of water (Mg. 110), in the midst of abody of water, its upper surface coinciding with the free surface of the liquid. Letthe prism be 4 cm deep and1 cm square at the end; thenthe area of one of its ends is1 cm^ and the volume of theprism is 4 cc. Now the weightof 4 cc of water is 4 g, hencethis prism must exert adownward pre
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1895
