After the data, observed by a U.S. tanker on and off the gulf Stream, the auther had the value of mean velocity and standard deviation of that current. According to G.I. Taylor (1922), if we put Rζ as a correlation coefficient of the velocities between two times intervaled by ζ houres and assume Rζ=e^<-ζ/A>, then the standard deviation of the position of a particle transported by turbulent motion is expressed as formula (4). The error of the estimated position was calculated by the data above mentioned and shown is formula (7), and this seems to be rather good approximation with Prof. Samejima's value.