246 [Recess, 



as in the case first considered in this paper, the instantaneous 

 pressure p i may be expressed in terms of its partial differential co- 

 efficients, and of the density at the point where the pressure is being 

 considered. 



It is also shown that, in the general case, where the whole or a 

 portion of the fluid is endued with velocity, the instantaneous pressure 

 may be ascertained by adding to the expression of the last paragraph 

 a term involving the density and the partial differential coefficients 

 of the velocity at the point where the pressure is being considered. 



It is finally shown that, in the case of the transmission of a pulse 

 through a cylindrical tube where the motions are small, the equation 

 of motion will be of this form, 



dt z dx* 



where x denotes the distance from the origin measured parallel to 

 the axis of a given stratum in the state of rest, y the same distance 

 at the time t, and a 2 and 2 are constants, the value of a 2 being the 

 same as in the ordinary theory. 



As this equation leads to the conclusion that there are two veloci- 

 ties, it results that, except perhaps in very rare instances, in which a 

 duplication has been observed in sounds heard at very great distances, 

 the proposed correction of the theory of the motion of elastic fluids 

 will not practically affect the theory of sound. 



By the method adopted in the case of elastic fluids, the author 

 conceives himself to have established that, in what are commonly 

 termed inelastic fluids, the pressure during motion will not be equal 

 in all directions. 



IV. "On the Nerves of the >Liver, Biliary Ducts, and Gall- 

 bladder." By ROBERT LEE, M.D., F.R.S. Received 

 August 18, 1862. 



(Abstract.) 



After adverting to the deficiency of existing knowledge respecting 

 the distribution and arrangement of the nerves of the liver, the 

 author states that he has recently made dissections which " prove 

 that all the arteries which ramify throughout the substance of the 

 liver, even the most minute, are accompanied with nerves, on which 



