In Part (1) the various types recently put forward to solve the high-voltage cable problem are discussed. The principle of the gas cable is stated, together with the advantages to be expected.Part (2) describes very briefly the experimental work on the basis of which the cables were made, and gives reasons for the choice of paper, gas, operating pressure, etc.Part (3) is devoted to the construction and performance of the actual cables. Examples are given which show their extreme stability, and also the accuracy with which their performance can be predicted. A series of typical designs are tabulated, and the advantages anticipated in Part (1) are shown to be realized.Part (4) deals with the design of gas-cable joints and sealing ends, and the methods used to maintain dryness during their making. The gas feeding arrangements and other accessory apparatus are also described.