In his lecture at the last meeting ofThe Society of RheologyDr. Erk considered the Engler viscometer and pointed out that the relationship between kinematic vicosity ν and Engler degreesEis adequately represented by Vogel's empirical equationν = E100 {7.6(1−1/E3)}. In contrast, as Dr. Erk also indicated, the theoretical equations of Mises and of the author show appreciable departures from experimental values. With regard to the equation considered by the author as an approximate equation for high viscosities, I have since found that an error was made in its derivation, so that the failure of the equation is not to be ascribed to the theory of laminar entrance‐flow. Meanwhile it has been demonstrated that the theory of laminar entrance‐flow, as far as one can expect it, actually agrees with observations and with Vogel's equation, as I should like to show you briefly.