Discussion on “experimental researches on skin effect in conductors,” (Kennelly, Laws and Pierce), San Francisco, Cal., Sept. 16, 1915. (see proceedings for August, 1915)

H. B. Dwight (by letter): In the discussion of the measurement of the skin effect resistance ratio of copper strips, spaced at 60 cm., it is stated that the large discrepancies between the theory for infinite strips, and the observations made, are believed to be due to power being dissipated by eddy currents. All distortions of current connected with skin effect may be called eddy currents, but where the conductors are far apart and carry sine wave currents, the distortions of current are regular, and this case of skin effect obeys very similar laws to those governing round conductors. In the case under discussion, formula (103) of the paper is used, which takes into account only the crowding of current, due to skin effect, toward the flat surface of the copper strips. A more important action is the crowding of current toward the edges of the strip, and this accounts for practically all of the skin effect observed at 60 cm. spacing.