Measurements are made on the viscosity of aqueous solutions of barium chloride at 18°C over the range 0.006 to 0.492 molality. The value of the constantAin the equation &eegr;=&eegr;c/&eegr;0=1+Ac½is determined and found to agree, within 4 percent, with the theoretical value of the constant as determined by Falkenhagen and Vernon. The constants of several empirical equations are also given.