In order to establish the national standards of neutron measurements, a manganese sulphate ($MnSO_4$) bath system was developed under the IAEA technical support. This bath system was made up of a spherical s.s. 316 L bath, of 3.5 mm thick and of 125 cm internal diagmeter, filled with a manganese sulphate solution, a solution circulating system, and a $^5Mn;{gamma}-ray$ monitoring system. The solution pumped from the bath was introduced into a Marinelli beaker-type monitor vessel which was equipped with two seperate detectors, $3.8cm{phi}{times}3.8cm$ NaI(T1) crystals. The performance of the system were tested using the neutron sources, $^{241}Am-Be;and;^{252}Cf$, mounted at the center of the bath. From the decay curve analysis of $^{56}Mn$ activity, neutron emission rate of $^{252}Cf$ by the comparative method was obtained to be $3.71{times}10^7;n/s;per;50{mu}g$ as of November 15, 1985.