In order to minimize the effect of extraneous disturbance in submarine telegraph cables operated duplex, it has been the practice for some time past to make the earth connection of the artificial line several miles from shore. For this purpose a length of twin-core cable was laid, the seaward end of the conductor of the second or sea-earth core being connected to the sheathing wires.With the advent of the loaded cable, in order to take full advantage of the possible great gain in speed a more effective method of interference elimination became necessary. The method now generally adopted provides for a twin core extending from theshore to a point where the cable reaches deep water. The seaward end of the second core is joined to a length of core having a stranded manganin-wire conductor, the free end of which is connected to the sheathing wires in the usual manner. This second core is termed the “balanced sea-earth”This paper deals with the problem of computing the value of the resistance of the manganin core for a taper-loaded cable.Mention is made of the function of a taper-loaded cable as a high-speed duplex telegraph cable.High or low freqencies referred to in the paper are within the band of telegraph signalling frequencies.