Abstract
The author observed a tidal current using his current meter [1]and two others of different kinds simultaneously. He explained that the observed velocity fluctuation with the period of 1.5 hours was caused by the instantaneous penetration of the waters broken from the disturbance, and the time variation of velocity was due to the effect of vertical eddy viscosity and the change of the surface slope with time Further. he analysed the shorter period disturbance and found that its eddy diffusion coefficient K∼269 c. g. s, its mean length of edddy l∼124 cm.
