abc u^y 



iH-* 



.,)iA)000"--I— 7?? aonifc 



320 Prof. Potter on the Solution of the Problem of Sound 



-cV V/Vo/- 



When we call the ordinary pressure of the atmosphere unity, we 

 have c= '000046 for water according to Canton, and c= "0000461 

 according to CErsted, when freed from air. According to Col- 

 ladon and Stui-m, c = '0000495 for the water of the lake of 

 Geneva in its ordinaiy condition, and c= ■0000513 when free 

 from ail-; but (Ersted has objected to the method of reducing 

 their results in allowing for the compression of the vessels used. 



Let a, b, c represent three 

 contiguous atoms in the hquid' '-'^ it^i'^'^— 

 at rest, 



a, 13, 7 their positions after 



displacement. *^ ' ' 



Let Ob=s ab = bc = 2Bs,^^^ ^,,^ 



0y8=S, jo=thepres. ^ -^ 



sure at b, &nd py the density, ^i .■.ijfnuiKc' 3f[f narl-p A bnr» oJ 



Then 28S being the distance of two contiguous atoms after a 

 disturbance, we have, considering the change of volume to take 

 place only in the direction of the wave motion, 



Let p become p' for the atoms a and /3, and p" for the: atonls 

 /S and 7, we have "'"' 



.bnoo:.^^^+ |^*+ «5W8^- -;^V 



«bmpil ni fam^oa i/f &T.|jfi+#-^^V "°'^^''^^"^" "'^^ 

 -fldoa^H ndoG ■^^ ^^f^p^ ^^^^^^^^^^^^ 



als«>JBW lol yiiool.v i.. dS , , \^^^^ ^l"^'^^ "^''i'lZZ 



U;di barrow Bd llrw.i, ^o. .f .5^ v^ l^I^^rf^a-^f "^ol' ^'^.f 



neglecting the higher teWriS of the serie^^^^*^, f .; ,^„ ' 



When there is no impressed force, the general equation of fluid 



motion becomes^ from my paper in the last Nunaber, 



/bjiiiiiooi. alii -'4^^'_ ^ _^ """■' ' " ;b9nim^at 



