The viscosities of the binary solutions of n-butyl alcohol and N-ethylaniline have been measured at 15.00℃ in an Ubbelohde viscometer.The fluidities of n-butyl alcohol and N-ethylaniline were found to be 29.61 and 39,06 rhes respectively,while the solution at ca.30 mole percent butyl alcohol shows a maximum fluidity of 41.10 rhes.