IN a lengthy article entitled “Milestones of Communication Progress”(Elect. Comm., 20, No. 3 ; 1942), H. T. Kohlhaas presents a comprehensive review of the developments in electrical communication which have occurred within the last twenty years. In the planning and co-ordinating of long-distance telephone communication, an outstanding event was the creation in 1924 of the International Consultative Committee on long-distance telephony in Europe, following a proposal made by Sir Frank Gill in his presidential address to the Institution of Electrical Engineers in 1922. Between 1923 and 1926 a succession of recorded steps led to the establishment of the first trans-Atlantic radiotelephony circuit between the United States and England. The first Madrid-Buenos Aires radiotelephone circuit was inaugurated in 1929 and it was followed in 1930 by the first radiotelephone circuit between the Americas. In 1931 the first demonstrations of single sideband short-wave radiotelephony were carried out between Buenos Aires and Madrid and between Madrid and Paris, establishing the now well-recognized improvements in transmission efficiency and the economies which this method makes possible.