Abstract
An attempt is made to give an idea to the question: at what horizontal expanses of a water basin will the effect of the Earth's rotation on the circulation become prominent. This is only possible if we utilize the horizontal eddy viscosity. This effect of the Earth's rotation is first perceptible when the critical value of a quantity μ=a3β/Al exceeds 185.6. This corresponds to a basin about three to five hundred kilometers across for the generally accepted values 107-108 of the coefficients of lateral eddy viscosity.
