The tower was assembled by piling up many unit tanks. The raw material solutions were fed in the top of the stages, there, emulsification was performed. The emulsion was ripened during the flowing down through the stages. When the containig amount V of emulsion in each stge was equal one another, raw material solntions were fed simultaneously in only the 1st stage; when V was equal, silver nitrate solution was fed separately in the 1st and the 2nd stages; and when V was not equal, raw material solutions were fed in only the 1st stage. The equations of these three cases were derived and were proved by the experiments. On heating and agitation, warm air blowing method was not adequate, but propellers for agitation connected with one axis passing through all stages and electric wire heater wound around the tower were adequate.